Air-to-Water Heat Pumps in Homes with Boilers

This project, funded by NYSERDA and led by Taitem Engineering, evaluated the viability of using air-to-water heat pumps at five homes that heat with hot water. The selection, installation, and monitoring of the demonstration sites was conducted from 2017 – 2019.

Over fifty homeowners applied to participate, and five demonstrations were conducted.

Fifteen air-to-water (ATW) heat pump products were evaluated.

Results

Air-to-water heat pumps were installed at all five demonstration sites and began operating during the 2018-2019 heating season. Data on efficiency and operation is still being collected for further analysis.

Is an Air-to-Water Heat Pump
a good fit for you?

Characteristics of good project candidates:

Efficient buildings with:

1) Radiant slab floor heating
2) High thermal mass
3) Low temperature hydronic heat
4) Low heating load

Buildings that have:

1) A large number of enclosed rooms
2) Existing electric or oil boiler heat
3) Objections or inability to heat with natural gas

Experienced early adopters:

Owners with a background and interest in HVAC systems and desire to pioneer a new technology.

What to know about Air-to-Water
Heat Pumps

‣ An air-to-water heat pump is not a one-to-one replacement for a boiler.

‣ All systems require a buffer tank to reduce cycling.

‣ Additional controls and back up heat will be needed.

‣ These products and the technology are still maturing.

Air-to-Water Heat Pump Generalizations

Often, but not always, true

Typically not a cost-effective option when compared with natural gas or air-to-air heat pump alternatives
They will not be able to carry the entire heating load, and they are not practical for people looking to divest themselves entirely from an existing fossil fuel heating system
Most practical installations will be limited in scope, with minimal changes made to heat emitters in the living spaces and continued use of the existing heating system to handle peak heating conditions
Not an ideal solution for absentee landlords, frequent travelers, camps or other limited use situations or locations with regular power outages
Still an emerging technology and best results are achieved when installed by ‘early adopters’ who enjoy ongoing experimentation and adjustments to optimize their system
Qualified installers and service providers may be difficult to find, and the installation process can be expensive