Your Heat Pump and Winter

During our usual snowy and humid winter months, heat pump owners should know the best tips and tricks to make sure their home’s heating system is a top performer.

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

Your outdoor compressor needs lots of good airflow.  This does not just mean behind and on the sides, but also in front. You want the compressor to have access to warmer outdoor air and it needs to be able to move the colder air produced away as easily as possible. Object up to ten feet in front of the compressor can cause cold air back flow which will reduce the ability of the unit to extract heat from the ambient air. Check after any big changes in snowfall and how it accumulates (plowing, shoveling, drifting, roof avalanches). 

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. This ice under the unit is normal and during extended cold spells, it can build up into a mini glacier. This refrozen condensate ice should not present any issues. If it seems to be creeping up along the back or sides of your outdoor unit, it is best to leave it alone and allow the drain pan heater and defrost cycles to keep it in check.

3. Watch for ice ON your external unit. 

Ice up on the unit itself, along the sides, back, and climbing up from the base, is often indicative of a performance issue, such a slow refrigerant leak. If you notice that external unit is icing up (lots of heavy frost) contact your installer immediately or contact one of the contractors here. Waiting too long for a repair can be detrimental to the lifespan of the system. One temporary trick to deice your compressor is to run the heat pump in AC mode for 15 – 20 minutes. While this will pump cool air into your home, it will send heat to the compressor and clear it of ice fairly quickly. Still, call a contractor for service – asap.

4. Increase the fan speed for greater heat distribution

Cold outdoor temperatures often require a slightly different approach to using your heat pump. Turning up the temperature with your remote will help of course. But, so will increasing the fan speed. By upping the fan speed, the heat pump will not only move more air across the indoor heat exchanger, it will push the warmed air further into your home. The AUTO fan setting is best for most occasions, but at night, it can help to run the fan more briskly. The louder fan will do its work while you sleep and you should wake to a warmer home. Turn the unit back to AUTO once you are up and about.

5. Check and clean the air filter on the interior unit…often. 

Winter is when your system needs its efficiency the most, so be sure it has good airflow.  Check the filter at least every two weeks and clean when necessary. The environment of the indoor unit can greatly influence the frequency of needed cleanings. Heat pumps in shops, for example, may need their filters cleaned of sawdust much more often.

6. 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 often where exposed water pipes tend to 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 of water running). 

7. 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 any risks.

8. 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 back rooms may 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. Consider moving this thermostat to a more isolated location. An electrician can do this for around $150.

9. 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. Don’t overdo it though. It will take a longer period of time to warm your home with a heat pump than with your old oil system. It is best to keep the temperature as steady as you can. A couple of degrees cooler at night is the most you should set the heat pump back.