Updated July 29, 2026: Air-to-water heat pump equipment, rebate rules, qualifying product lists and permit requirements can change. Confirm the current program, equipment eligibility and project requirements before ordering equipment or removing an existing boiler.
An air-to-water heat pump transfers heat between outdoor air and a water-based hydronic system. Instead of heating indoor air directly, the heat pump supplies heated water or water-glycol solution to compatible radiant floors, radiators or hydronic fan coils.
Air-to-water systems can be especially attractive in BC homes that already use boiler-based radiant-floor heating or other low-temperature hydronic distribution. They can also be used in new construction designed around low water temperatures.
The critical design issue is not simply whether the home already has pipes and radiators. Heat pump efficiency and capacity depend strongly on the required hydronic water temperature. A system designed around relatively cool radiant-floor water is a very different application from an older radiator system that requires very hot water during winter.
This guide explains air-to-water heat pump operation, water temperature, radiators, radiant floors, fan coils, cooling, domestic hot water, backup heating, electrical requirements, commissioning and current BC incentive considerations.
What Is an Air-to-Water Heat Pump?
An air-to-water heat pump is an air-source heat pump that transfers thermal energy between outdoor air and a water-based distribution system.
During Heating
The heat pump:
- Absorbs heat from outdoor air.
- Raises the refrigerant temperature using a compressor.
- Transfers that heat through a heat exchanger.
- Warms water or a water-glycol mixture.
- Circulates the heated fluid through the building.
The Hydronic System Can Serve:
- Radiant floors
- Low-temperature radiators
- Panel radiators
- Hydronic fan coils
- Other compatible hydronic emitters
It Is Not the Same as a Heat Pump Water Heater
A conventional heat pump water heater primarily produces domestic hot water for:
- Showers
- Baths
- Sinks
- Household hot-water use
An air-to-water space-heating system is designed around the building’s hydronic heating load.
Some specialized systems can provide both space heating and domestic hot water, but that requires a combined-system design rather than assuming one function automatically provides the other.
How Does an Air-to-Water Heat Pump Work?
The refrigeration process is similar to other air-source heat pumps.
Outdoor Unit
The outdoor equipment contains components such as:
- Outdoor coil
- Compressor
- Fan
- Reversing valve where applicable
- Electronic controls
Hydronic Heat Exchanger
Instead of transferring heat to indoor air through a conventional air handler, the refrigeration circuit transfers energy into a water-based loop.
Hydronic Module or Hydrobox
Depending on equipment design, the system may use an indoor module to manage:
- Water flow
- Pumps
- Temperatures
- Zones
- Backup heat
- Domestic hot-water priority where applicable
Building Distribution
The heated water is sent to the hydronic emitters.
Heat then reaches the rooms through:
- Radiant surfaces
- Natural convection
- Fan-assisted airflow
depending on the emitter type.
Air-to-Water vs Air-to-Air Heat Pump
| Feature | Air-to-Water | Air-to-Air |
|---|---|---|
| Outdoor energy source | Outdoor air | Outdoor air |
| Indoor heat distribution | Hydronic water | Indoor air |
| Radiant-floor compatibility | Yes, where properly designed | No direct hydronic connection |
| Radiator compatibility | Possible depending on water temperature and emitter output | Not directly |
| Ductless wall units | Not required for hydronic heating | Common option |
| Central ducts | Not required for radiant or radiator heating | Required for central ducted configuration |
| Cooling | Possible with suitable chilled-water terminals and controls | Directly available through indoor air units |
| Primary retrofit opportunity | Boiler or hydronic homes | Furnace, baseboard or general HVAC retrofits |
Neither Is Automatically Better
The choice depends heavily on the home’s existing distribution system.
A home with high-quality radiant-floor tubing already installed has a very different starting point from a home with no hydronic system at all.
1. Hydronic Water Temperature Is Critical
Required water temperature is one of the first questions that should be answered in an air-to-water project.
Lower Water Temperatures Are Generally Better for Heat Pump Efficiency
Natural Resources Canada explains that air-to-water heat pumps operate more efficiently when producing water below approximately 45°C to 50°C.
Why?
The compressor has to create a temperature difference between:
- The outdoor heat source
- The hydronic delivery temperature
As the required water temperature increases, the refrigeration system generally has to work harder.
High-Temperature Hydronic Systems Need Extra Care
NRCan advises caution with high-temperature radiators requiring water above approximately 60°C because those temperatures generally exceed the limits of many residential heat pumps.
The Correct Question
Do not ask only:
What is the maximum water temperature?
Ask:
What heating capacity and COP does this exact system provide at our required water temperature and winter outdoor condition?
2. Radiant Floors Can Be an Excellent Match
Hydronic radiant-floor heating often uses relatively low supply-water temperatures.
That can make it a strong application for air-to-water heat pumps.
Radiant Floors Have Large Heat-Transfer Area
Instead of concentrating heating in a small radiator, a large portion of the floor becomes the emitter.
That allows useful room heat output without requiring extremely hot water in many designs.
Actual Performance Depends On:
- Tube spacing
- Floor construction
- Slab thickness
- Floor covering
- Water flow
- Design water temperature
- Room heat loss
Floor Coverings Matter
Tile, concrete, hardwood and carpet do not transfer heat identically.
The design should account for the thermal resistance and manufacturer temperature limits of the finished floor.
Thermal Mass Matters
A concrete slab can store a significant amount of thermal energy.
Large daily thermostat setbacks may therefore create slow recovery and unnecessary high-water-temperature demand.
3. Existing Radiators Need Evaluation Before Conversion
An existing radiator may work very well, moderately well or poorly with a heat pump.
The answer comes from heat output at the proposed water temperature.
Check:
- Room heating load
- Radiator dimensions
- Radiator type
- Water flow
- Supply temperature
- Return temperature
Old Radiators Are Not Automatically Bad
Large cast-iron radiators can have substantial surface area.
If the building has also received:
- Insulation upgrades
- Air sealing
- Better windows
the current room heat load may be lower than when the radiator system was originally installed.
Possible Solutions When Output Is Too Low
- Larger radiator
- Additional radiator
- Low-temperature panel radiator
- Fan-assisted radiator
- Hydronic fan coil
- Building-envelope improvements
4. Hydronic Baseboards Can Be More Challenging
Hydronic fin-tube baseboard should not be confused with electric resistance baseboard heating.
Hydronic baseboard receives hot water from a boiler or other hydronic heat source.
Output Falls as Water Temperature Falls
A system designed around high-temperature boiler water may not provide enough room heat when connected to a lower-temperature heat pump.
Possible Retrofit Strategies Include:
- Adding more emitter length
- Replacing fin-tube sections
- Installing panel radiators
- Adding fan coils
- Reducing the building heat load
Do Not Size the Heat Pump to Compensate for an Inadequate Emitter
A larger outdoor heat pump does not solve a room radiator that cannot release enough heat at the selected water temperature.
5. Hydronic Fan Coils Can Provide Heating and Cooling
A fan coil circulates indoor air across a water coil.
During Heating
Warm hydronic water transfers energy to the room air.
During Cooling
A suitable fan coil can receive chilled water and remove:
- Indoor heat
- Indoor moisture
Why Fan Coils Can Work Well With Heat Pumps
Fan-assisted heat transfer can provide useful room heating at lower water temperatures than some passive radiator systems.
Cooling Requires Condensate Control
The fan coil needs:
- Insulated cold-water piping
- Drain pan
- Condensate drain
- Appropriate controls
Any surface below the air dew point can collect moisture, which is why chilled-water piping cannot be treated like ordinary heating pipework.
6. Cooling Requires a Different Distribution Strategy
Air-to-water equipment may be capable of producing chilled water, but that does not mean every existing hydronic system can provide cooling.
Existing Heating Radiators
Traditional radiators normally lack:
- Condensate pans
- Drainage
- Cold-pipe insulation
- Air movement needed for practical cooling
Radiant Slab Cooling
Better Homes BC notes that radiant slab cooling is possible but has limited output and creates a risk of condensation.
Dew Point Is Critical
If floor-surface temperature falls below the dew point, water can condense on the surface.
This can create:
- Slippery surfaces
- Moisture damage
- Mould risk
Fan Coils Are Often the More Practical Cooling Terminal
They are designed to handle chilled water, moving air and condensate when selected for that purpose.
7. Domestic Hot Water Is a Separate Design Question
Air-to-water space heating and domestic hot water are related technologies, but they are not automatically the same system.
Space Heating May Need:
- 30°C to 40°C water for some radiant applications
- Higher temperatures for other emitters
Domestic Hot Water Has Different Requirements
It involves:
- Potable water
- Storage volume
- Recovery rate
- Sanitation temperature requirements
- Peak household demand
Possible Designs Include:
- Air-to-water heat pump for space heating only
- Combined space and domestic water heat pump
- Space-heating heat pump plus separate heat pump water heater
- Another separate water-heating system
Do Not Remove a Combi Boiler Without Replacing Both Jobs
If the existing boiler heats the home and domestic water, the new project must address both loads.
8. Cold-Weather Capacity Still Matters
The hydronic distribution system does not remove the need to understand outdoor heat-pump performance.
As Outdoor Temperature Drops:
- The building heating load normally increases.
- Available heat-pump capacity can change.
- COP can change.
- Defrost becomes part of operation.
At the Same Time, the Hydronic System May Demand Hotter Water
This creates a challenging combination:
- Colder outdoor source temperature
- Higher indoor delivery temperature
Check the Actual Performance Map
The designer should confirm capacity at:
- Relevant outdoor temperature
- Required leaving-water temperature
rather than relying on nominal equipment capacity alone.
A 12 kW Heat Pump Is Not Necessarily a 12 kW Heat Pump Under Every Condition
Published nominal capacity is only one operating point.
9. Backup Heating Must Be Designed
Backup heating can serve several purposes.
Peak-Load Backup
Additional heat may be required if the heat pump is intentionally sized below the absolute peak building load.
Emergency Backup
The home may need a way to maintain safe temperature if the heat pump is out of service.
Domestic Hot-Water Backup
Combined systems may use additional electric heating for high water-temperature or recovery demands.
Possible Backup Sources
Depending on system design and applicable program rules:
- Electric resistance heater
- Electric boiler
- Other permitted electric heating
- Retained fuel equipment in hybrid projects that are not subject to full-conversion requirements
Rebate Rules Can Change the Available Choices
A technically functional hybrid design may not meet an incentive pathway requiring removal of fossil-fuel heating equipment.
10. A Heat-Load Calculation Is Essential
Do not size an air-to-water heat pump from the boiler nameplate.
Existing Boilers Are Frequently Larger Than the Current Building Load
The home may also have changed since the boiler was installed through:
- Attic insulation
- Wall insulation
- Window replacement
- Air sealing
- Renovation
Calculate the Current Building Load
The analysis should consider:
- Outdoor design condition
- Wall construction
- Windows
- Doors
- Ceiling and roof
- Foundation
- Air leakage
Then Evaluate the Hydronic Emitters
Each important room needs enough emitter capacity at the intended design water temperature.
This Creates Two Matching Problems
- Match heat pump capacity to building load.
- Match emitter output to room load.
Ignoring either one can create an expensive system that technically operates while the homeowner remains cold.
11. Hydronic Flow and System Volume Matter
Air-to-water heat pumps need a stable hydraulic system as well as a correctly sized compressor.
Important Hydronic Variables Include:
- Flow rate
- Pressure drop
- System water volume
- Zone-valve operation
- Pump sizing
- Expansion capacity
- Air removal
Small Active Zones Can Create Problems
Imagine a system designed for a large home while only one small bathroom zone is open.
The active water volume and heat demand may be much smaller than the heat pump’s minimum stable output.
Possible Result
- Rapid water-temperature rise
- Short compressor cycles
- Control instability
Hydraulic Design Must Match the Heat Pump
This may involve:
- Buffer storage
- Hydraulic separation
- Variable-speed pumping
- Zone-control strategy
depending on the equipment and building.
12. Electrical Requirements Can Change Significantly
A gas-boiler home may currently use relatively little electricity for space heating.
Converting to an air-to-water heat pump moves much of that heating load onto the electrical system.
The Electrical Review Can Include:
- Outdoor heat pump
- Indoor hydronic module
- Circulation pumps
- Backup electric heat
- Fan coils
- Domestic water-heating equipment
Panel Size Alone Does Not Answer the Question
An electrical load assessment should consider:
- Existing household loads
- Service capacity
- Panel condition
- Heat pump electrical specifications
- Future equipment such as EV charging
Do Not Promise a Service Upgrade Before the Assessment
Some projects need significant electrical work.
Others can be designed within the available service.
13. Commissioning Is More Than Turning the System On
An air-to-water system combines refrigeration and hydronics.
Both sides need commissioning.
Refrigeration Checks May Include:
- Equipment configuration
- Installation testing
- Manufacturer-required evacuation procedures where applicable
- Refrigerant charge verification
- Operating temperatures
- Operating pressures
- Fault information
Hydronic Checks May Include:
- System pressure
- Flow rate
- Pump operation
- Water or glycol condition
- Expansion tank
- Air elimination
- Zone valves
- Buffer tank where installed
Temperature Checks
Confirm:
- Supply-water temperature
- Return-water temperature
- Temperature difference across the hydronic circuit
- Room response
Control Checks
Commission:
- Thermostats
- Outdoor-reset curve where used
- Backup heat
- Domestic hot-water priority
- Cooling mode and condensation protection where applicable
A Warm Pipe Does Not Prove a Successful Installation
The system needs to meet building demand while operating within its designed temperatures, flow rates and equipment limits.
14. BC Rebates and Permits Have Specific Requirements
Air-to-water projects can involve both electrical heat-pump regulations and removal of existing heating equipment.
Electrical Permit
Technical Safety BC currently states that most residential heat pump installations or upgrades require an electrical permit.
Existing Natural Gas Boiler
If a natural gas boiler is removed or modified, applicable gas permits and regulated gas work are also required.
Additional Refrigeration Requirements
Technical Safety BC notes that residential heat pumps become regulated refrigeration equipment under additional rules in certain situations, including specific building-size, compressor-power and refrigerant conditions.
Current Energy Savings Program
Better Homes BC currently has an air-to-water heat pump pathway for qualifying homes converting from:
- Fossil fuel
- Electricity
- Wood
Current Requirements Include:
- Heat pump sized as the primary heating system
- Serving a main living area
- Eligible equipment
- Installation according to program requirements
- Registered contractor requirements
- Applicable permit and bylaw compliance
Fossil-Fuel Conversions Have Additional Removal Requirements
Current program rules require the applicable primary fossil-fuel heating equipment to be removed for the full-conversion pathway.
Verify Before Installation
The incentive program, product list and eligibility rules should be confirmed before equipment is ordered.
Does an Air-to-Water Heat Pump Need a Buffer Tank?
Sometimes. Not automatically.
A Buffer Tank May Be Used To:
- Increase system water volume
- Reduce rapid temperature changes
- Help prevent short cycling
- Hydraulically separate circuits
- Support several hydronic zones
But a Buffer Tank Has Costs
It can add:
- Equipment cost
- Mechanical-room space
- Heat loss
- Piping complexity
Do Not Install One by Habit
Determine whether the system needs it based on:
- Manufacturer requirements
- Minimum water volume
- Minimum flow
- Number and size of zones
- Heat pump minimum output
What Is Outdoor-Reset Control?
Outdoor-reset control adjusts the hydronic supply temperature according to outdoor conditions.
When It Is Mild Outside
The building needs less heat.
The system may be able to operate with cooler supply water.
When It Gets Colder
Water temperature can increase according to the designed heating curve.
Why This Can Help a Heat Pump
The heat pump avoids producing unnecessarily hot water during most of the heating season.
Lower water temperature can support better operating efficiency.
The Curve Needs Commissioning
If set too low:
- Rooms may not reach setpoint.
If set unnecessarily high:
- Heat pump efficiency can suffer.
The Objective
Supply the lowest water temperature that still allows the home to maintain comfort under the current load.
Can an Air-to-Water Heat Pump Replace an Existing Gas Boiler?
Yes, when the heat pump and hydronic system can provide the required heating performance.
Before Removing the Boiler, Determine:
- Building heat load
- Existing boiler function
- Radiator or radiant-floor capacity
- Required design water temperature
- Electrical requirements
- Backup strategy
- Domestic hot-water requirements
Do Not Size From the Boiler Rating
A 100,000 BTU/h boiler does not prove the home currently requires 100,000 BTU/h of heat.
Existing Hydronic Problems Should Be Corrected
Inspect:
- Circulation pumps
- Zone valves
- Expansion tank
- Air removal
- Leaks
- Emitter balancing
before relying on the system as the distribution network for new heat pump equipment.
What if the Existing Boiler Also Provides Domestic Hot Water?
A combination boiler can serve both:
- Space heating
- Domestic hot water
Removing It Creates Two Replacement Loads
A project that addresses only space heating leaves the home without the domestic-water service previously supplied by the boiler.
Possible Replacement Designs
- Combined air-to-water space and hot-water heat pump
- Air-to-water space-heating system plus separate heat pump water heater
- Another compliant water-heating system
Current BC Program Requirements
Better Homes BC currently instructs applicants replacing certain fossil-fuel combination boilers to obtain specific instructions and pre-approval regarding removal of hydronic space-heating equipment.
Do This Before Demolition
Rebate paperwork becomes considerably less philosophical when the boiler is still attached to the wall.
How Efficient Is an Air-to-Water Heat Pump?
There is no single COP that represents an entire heating season.
Efficiency Changes With:
- Outdoor temperature
- Leaving-water temperature
- Return-water temperature
- Compressor modulation
- Defrost
- System controls
Water Temperature Is Particularly Important
For example, the same heat pump can operate more efficiently supplying moderately warm radiant-floor water than producing substantially hotter water for legacy emitters.
Use Manufacturer Performance Tables
Compare:
- Heating output
- COP
- Outdoor temperature
- Leaving-water temperature
at conditions relevant to the actual project.
Do Not Compare Maximum COP With Boiler AFUE Directly
Use seasonal operating conditions and current utility costs for any meaningful economic comparison.
How Should Air-to-Water Heat Pump Operating Cost Be Estimated?
The building needs a certain amount of useful heat over the heating season.
The heat pump electricity requirement depends on the efficiency with which that heat is delivered.
Estimate Using:
- Building heating demand
- Heat pump seasonal performance
- Hydronic water-temperature profile
- Backup heating
- Current electricity rates
For Gas-Boiler Replacement
Compare:
- Existing annual gas consumption
- Boiler efficiency
- Fixed gas charges
- Expected heat pump electricity
- Any remaining gas appliances
Removing the Last Gas Appliance Can Change the Comparison
If the gas account is no longer required, fixed gas-service costs may also be removed.
If Gas Remains
For a fireplace, range or other appliance, those fixed charges may continue.
No Responsible Contractor Can Promise One Universal Monthly Cost
Water temperature alone can make two otherwise similar homes use meaningfully different amounts of electricity.
Air-to-Water Heat Pump Installation Process
Step 1: Assess the Home and Existing Hydronic System
Document:
- Building layout
- Existing boiler
- Heating fuel
- Radiators
- Radiant-floor zones
- Domestic hot water
- Electrical service
Step 2: Calculate the Heating Load
Determine the current building heating requirement using an appropriate recognized method.
Step 3: Evaluate Hydronic Emitters
Determine what water temperature each zone requires to satisfy its load.
Step 4: Select Equipment
Compare the heat pump’s capacity and efficiency at:
- Relevant winter outdoor conditions
- Required water temperatures
Step 5: Design the Hydraulic System
Determine requirements for:
- Pumps
- Buffer tank
- Expansion tank
- Zone valves
- Hydraulic separation
- Glycol where applicable
Step 6: Plan Backup Heating
Confirm capacity, controls and electrical requirements.
Step 7: Plan Domestic Hot Water
Required where the existing boiler serves both functions.
Step 8: Confirm Electrical Work and Permits
Review the complete project before equipment is ordered.
Step 9: Confirm Incentive Eligibility
Where applicable, verify:
- Program
- Income eligibility
- Contractor status
- Qualifying equipment
- Existing heating-system requirements
- Removal requirements
Step 10: Install and Commission
Verify refrigeration, hydronics, controls, backup heat and room performance before final handover.
What Should an Air-to-Water Heat Pump Quote Include?
| Quote Item | What Should Be Specified |
|---|---|
| Outdoor heat pump | Exact model and published capacity |
| Design conditions | Outdoor temperature and design water temperature used for selection |
| Heat load | How the building heating requirement was established |
| Emitters | Radiators, floors or fan coils being retained or changed |
| Hydronic module | Hydrobox or equivalent equipment |
| Pumps | New or retained circulation equipment |
| Buffer tank | Whether required and why |
| Backup heating | Type, capacity and control strategy |
| Domestic hot water | How it will be supplied after conversion |
| Cooling | Whether included and which terminals provide it |
| Electrical work | Circuits, disconnects, panel or service work |
| Existing boiler | Retained, removed or decommissioned |
| Permits | Electrical, gas and other applicable permits |
| Rebate | Program assumptions and documentation responsibilities |
| Commissioning | Refrigeration, hydronic and control testing |
| Warranty | Manufacturer and labour terms |
Air-to-Water Heat Pump Installation Red Flags
No Heat-Load Calculation
The boiler nameplate is not the building heating load.
No Discussion of Water Temperature
This is one of the largest warning signs in a hydronic heat pump proposal.
“Your Existing Radiators Will Be Fine” Without Calculations
Radiator output should be checked at the proposed heat pump water temperature.
Only Maximum Heat Pump Capacity Is Shown
Ask for capacity at the actual:
- Winter outdoor temperature
- Leaving-water temperature
No Minimum Flow or Zone Discussion
Hydronic zoning can affect heat pump operation significantly.
A Buffer Tank Is Added Without Explanation
Ask what hydraulic or operational problem it is solving.
Cooling Is Promised Through Existing Radiators
Ask how condensation, airflow and drainage will be handled.
Combi Boiler Is Removed Without a Hot-Water Plan
Space heating is only half of that appliance’s job.
Fossil-Fuel Equipment Removal Is Ignored
Gas equipment cannot simply be abandoned without following applicable safety and permit requirements.
The Rebate Is Guaranteed Before Eligibility Review
Current program eligibility depends on the household, fuel, equipment, contractor and installation.
Air-to-Water Heat Pump Planning in Metro Vancouver and Fraser Valley
Bernoulli Heating and Cooling provides free estimates for new heat pump installation projects across Metro Vancouver and Fraser Valley.
For boiler and hydronic homes, a useful assessment may include the home heating load, existing boiler, radiator or radiant-floor system, required water temperatures, cooling goals, electrical capacity, backup heating and equipment location.
New heat pump installation estimates are free.
For existing heat pump systems requiring troubleshooting, the current diagnostic appointment charge is $135. Repair labour, refrigerant, replacement parts and additional materials are separate.
Call 604-518-4438 or email heatingbernoulli@gmail.com.
Explore local heat pump installation information:
Air-to-Water Heat Pump: Frequently Asked Questions
What is an air-to-water heat pump?
It is an air-source heat pump that transfers thermal energy from outdoor air into a water-based hydronic heating system.
Is an air-to-water heat pump the same as a heat pump water heater?
No. An air-to-water heating system is designed around hydronic space heating, while a heat pump water heater primarily heats potable domestic water.
Can one system provide both space heating and hot water?
Some combined systems can, but both space-heating and domestic-hot-water loads and temperatures must be designed for explicitly.
Can an air-to-water heat pump replace a boiler?
Yes when the heat pump, emitters, hydronic system and electrical infrastructure are designed to meet the building heating load.
Can I keep my existing radiators?
Possibly. Their output must be checked at the lower water temperatures expected from the new system.
Can cast-iron radiators work with an air-to-water heat pump?
They can in suitable applications, particularly when they have enough surface area and the building heating load is low enough for reduced water temperatures.
Can hydronic baseboards work?
Sometimes, but conventional fin-tube baseboard can lose substantial output at lower water temperatures and needs careful evaluation.
Is radiant floor heating good for air-to-water heat pumps?
Often yes. Many radiant-floor systems can operate at lower water temperatures that are favourable for heat pump efficiency.
What water temperature does an air-to-water heat pump use?
It depends on the system. NRCan notes that heat pumps generally operate more efficiently below approximately 45°C to 50°C.
Can an air-to-water heat pump make 60°C water?
Some models may operate at high leaving-water temperatures, but capacity and efficiency should be checked at those conditions. NRCan notes that temperatures above roughly 60°C generally exceed the limits of many residential heat pumps.
Why does lower water temperature improve efficiency?
It reduces the temperature lift the refrigeration system must produce between the outdoor heat source and the hydronic delivery system.
What is leaving-water temperature?
It is the temperature of the hydronic fluid leaving the heat pump or hydronic heating module toward the building distribution system.
What is return-water temperature?
It is the temperature of the fluid returning from the building emitters to the heat source.
Can an air-to-water heat pump provide cooling?
Yes in systems designed for chilled-water operation, but the terminals, piping, controls and condensate management must all be suitable for cooling.
Can existing radiators cool the home?
Traditional heating radiators are generally not designed for chilled-water cooling, airflow or condensate management.
Can radiant floors be used for cooling?
Radiant cooling is possible in some designs, but output is limited and surface temperature must remain above the dew point to prevent condensation.
What is a hydronic fan coil?
It is a terminal unit that moves room air across a water coil. Suitable fan coils can provide both heating and cooling.
Why are fan coils useful with air-to-water heat pumps?
Fan-assisted heat transfer can provide useful heating at lower water temperatures than some passive emitters and can also support chilled-water cooling.
Does an air-to-water heat pump need a buffer tank?
Not always. The need depends on manufacturer requirements, system water volume, zoning, minimum flow and heat pump minimum output.
What does a buffer tank do?
It can increase thermal mass, stabilize temperatures, reduce short cycling or provide hydraulic separation in certain system designs.
Can too many small zones cause problems?
Yes. Small active zones can reduce water volume and heat demand below the heat pump’s preferred operating range, which may contribute to short cycling or unstable control.
Why does minimum flow matter?
The heat pump needs adequate hydronic flow through its heat exchanger. Poor flow can cause faults, poor performance or unstable operation.
Can existing circulation pumps be reused?
Possibly, but their flow, head, controls and compatibility with the new hydraulic design need to be checked.
Can existing zone valves be reused?
Possibly. Their flow characteristics and effect on minimum system flow must be evaluated.
What is outdoor-reset control?
It adjusts hydronic supply-water temperature according to outdoor temperature so the system can use lower water temperatures when the building load is lower.
Why is outdoor reset useful with a heat pump?
Lower water temperature during mild weather can reduce compressor temperature lift and improve operating efficiency.
Does an air-to-water heat pump work below freezing?
Yes, suitable equipment can operate below freezing, but capacity and COP vary with outdoor temperature and required water temperature.
Does it need backup heat?
That depends on the building load, heat pump capacity at design conditions, hydronic water temperature and the selected system strategy.
Can I keep my gas boiler as backup?
Technically this can be possible in a hybrid design, but it may not satisfy a rebate pathway that requires removal of the primary fossil-fuel heating system.
Can an air-to-water heat pump replace an electric boiler?
Yes in suitable hydronic applications, provided the heat pump, emitters and electrical system are designed for the building load.
Is an air-to-water heat pump more efficient than an electric boiler?
It can be because an electric boiler uses resistance heating while a heat pump transfers additional heat from outdoors and can operate at a COP above 1.
Is an air-to-water heat pump cheaper to run than a gas boiler?
It depends on heat pump COP, required water temperature, outdoor conditions, boiler efficiency, electricity rates and gas rates.
Can it heat domestic hot water too?
Some systems can provide or contribute to domestic hot-water production, but the potable-water load, storage, recovery and temperature requirements need separate design.
What if I currently have a combi boiler?
The replacement project must address both space heating and domestic hot water. Current Better Homes BC rules can also require specific instructions and pre-approval for some fossil-fuel combi-boiler conversions.
Do I need a heat-load calculation?
Yes for responsible system design. It is needed to select heat pump capacity and to confirm that existing emitters can meet room loads at the intended water temperature.
Can I size the new system from the old boiler rating?
No. Existing boiler capacity may be much larger than the home’s current heating load.
Can insulation upgrades help an air-to-water conversion?
Yes. Reducing heat loss can lower required emitter output, water temperature and heat pump capacity.
Can better insulation make old radiators more suitable?
Potentially. Lower room heat loss means the radiators can meet demand with lower water temperatures.
Does an air-to-water system need an electrical permit in BC?
Technical Safety BC states that most residential heat pump installations or upgrades require an electrical permit.
Does removing a gas boiler require a gas permit?
Applicable gas alteration or removal work requires the appropriate gas permit and qualified work.
Can I simply shut off and abandon the old gas boiler?
No. Gas equipment and piping are regulated and must be left safe and compliant under applicable permit and qualification requirements.
Will I need a 200-amp electrical service?
Not automatically. A proper electrical load assessment should consider the heat pump, backup heat, pumps, water heating and other household loads.
Can an air-to-water heat pump short cycle?
Yes. Oversizing, insufficient system volume, small zones, low flow or control problems can contribute to frequent cycling.
Can a buffer tank help reduce short cycling?
It can in some designs by adding thermal mass or hydraulic separation, but it should be selected to solve a defined system requirement.
What should commissioning include?
Commissioning should include refrigeration operation, hydronic flow, system pressure, supply and return temperatures, pumps, zones, controls, backup heat and room response.
What should a contractor inspect before quoting?
The building heat load, existing boiler, hydronic piping, emitters, required water temperatures, electrical service, domestic hot water, cooling goals and backup-heating strategy.
What is the biggest mistake in an air-to-water retrofit?
Choosing equipment before determining the building heat load and the water temperature required for the existing emitters to satisfy that load.
Are there BC rebates for air-to-water heat pumps?
Current Better Homes BC programs include qualifying air-to-water pathways, but eligibility depends on the program, household, existing fuel, equipment, contractor and installation requirements.
Does every air-to-water heat pump qualify for a rebate?
No. The current qualifying equipment list and program conditions must be checked before installation.
Does the heat pump need to be the primary heating system for rebates?
Current applicable program pathways can require the new heat pump to be sized and installed as the primary heating system.
Can I keep fossil-fuel heating and still receive the same conversion rebate?
Do not assume so. Current full-conversion pathways can require removal of the primary fossil-fuel heating equipment.
Does Bernoulli provide air-to-water heat pump estimates?
Bernoulli Heating and Cooling currently provides free estimates for new heat pump installation projects across Metro Vancouver and Fraser Valley.
How much is a diagnostic appointment for an existing heat pump?
The current diagnostic appointment charge is $135. Repair labour, refrigerant, replacement parts and additional materials are separate.