Using Heat Pumps in Cold Climates

river surround by bare tree top view

With our winter fast approaching, heat pump owners should know the best tips to make sure their home’s heating system is a top performer. These are especially important for owners going into their first winter of heat pump operation.

1. Make sure your external unit doesn’t get buried or confined by snow. 

You want lots of good airflow.  Check after any big changes in snowfall or how it accumulates (plowing, shoveling, drifting, roofavalanches). 

2. Watch for ice under your external unit. 

The compressor naturally drips condensate.  In winter this can freeze and make a walking hazard depending on the location of the external unit.  Don’t slip!

3. Watch for ice ON your external unit. 

This usually means there was a slow refrigerant leak when the unit was installed in warmer times, and now that it’s cold, it can’t operate.  If your whole external unit ices up (lots of heavy frost) contact your installer immediately, and make plans to use a backup heat system until they can fix it.

4. Check and clean the dust filter on the interior unit. 

Winter is when your system needs its efficiency the most, so be sure it has good airflow.  Check at the start of winter, and periodically throughout the year to get a feel for how often this needs doing (heat pumps in shops, for example, need their filters cleaned of sawdust much more often).

5. Watch your pipes! 

Especially when your heat pump upgrade goes through its first winter, check your pipes when it gets really cold to make sure they don’t start to freeze.  Eliminating a boiler, or reducing its use, eliminates waste heat in the boiler room, which is where lots of water pipes also live.  Keep an eye on them when it gets cold, and take measures to warm them up if necessary (heat tape, extra sources of heat, leave a very tiny trickle running). 

6. Watch your hydronic baseboards! 

Just like the situation above, if you still have a boiler for backup heat, make sure that the spaces your baseboard piping is in don’t freeze (baseboards often run around the cold perimeters of houses, so they are particularly vulnerable).  Run the system a little, perhaps, just to avoid and risks.

7. Check your system balance and thermostat harmony. 

If you have two different heating systems, make sure that your thermostats are in locations and at settings that will work together, in the most efficient way possible.  If you have a heat pump in your main living space and a different kind of heat in your other rooms, you want your heat pump to turn on first and produce as much efficient heat as it can before the other systems turn on (especially in homes with forced air, where the backup system is otherwise heating the same space as the heat pump).  Make sure that other system does turn on, though, or that back rooms will get too cold.  If the thermostat for the back bedrooms is in the same room as the heat pump, it will never click on because it’s always nice and warm.

8. Check your thermostat setbacks. 

You don’t want a ton of variation (“set it and forget it”), but our own experiments show that some amount of nighttime setback is beneficial in creating even more cost savings.