Plan Your Combined HVAC System Upgrade Project Carefully

Generally, GreenHomes recommends improving your home’s insulation levels and reducing your home’s air leakage rate prior to installing high-efficiency heating/cooling (HVAC) equipment. This is done so you can more accurately match the furnace, boiler or air conditioner size to the heating/cooling demands (also called heating/cooling loads) of your home. However, if your heating system is very old, inefficient and unreliable, installing new heating equipment and/or a new duct system as a priority to make sure your home will have heat in harsh, wintertime conditions is important. As a result, learn more about implementing and planning a combined HVAC system upgrade.

When upgrading your older, existing heating system, follow these steps:

1. Air seal and insulate your home whenever possible as part of your heating system upgrade
2. Make sure an ACCA Manual J type of heating/cooling load calculation is completed
3. Select a high-efficiency combination system (93% AFUE or greater for natural gas and propane gas systems)
4. Include duct sealing and duct insulation or heating pipe insulation as part of the combination system upgrade
5. Don’t forget - Proper maintenance of your new combination system is important!

Remember, combination units can be used in the following configurations:

1. With an air handling unit to provide forced air heating (like a furnace). This configuration allows for easy inclusion of central air conditioning to the system.
2. With hydronic heating piping (like a traditional boiler) using baseboard fin-tube or radiators.
3. With in-floor heating piping to provide radiant heating.
4. As an instantaneous or on-demand water heater that can provide an endless supply of hot water.

Overall, combination systems provide all hot water needs for the home (heating and domestic hot water) reliably with a high level of efficiency.