You might be surprised by some of the ways a heat pump works differently than a boiler or furnace. If you want to minimize your energy use and maximize your comfort, Efficiency Vermont offers a few tips on what not to do.
1. DON’T worry about the temperature reading.
A heat pump measures ambient room temperature differently than your old heating system. Set your heat pump to a comfortable temperature, then adjust the setting up or down over the course of a few days until you’ve reached the temperature number that feels right to you.
2. DON’T leave your existing heating system cranked up.
If you do, your old system will compete with the heat pump, costing you energy and money. In the area where you’re using your heat pump, turn your old thermostat 10°F lower than you used to. If you used to set it to 68, turn it to 58. This allows your old system to become the backup heat source. If the area gets chilly during a severe cold snap, don’t be afraid to turn up the old thermostat temporarily.
3. DON’T fuss with it every day.
You may have lowered the temperature on your old heating system when you went to work or at night. A heat pump is different. It reaches peak efficiency by maintaining a set temperature. Find the right setting (see #1), then leave it alone and let it work! Exception: for absences of over 24 hours, go ahead and turn it down.
4. DON’T go easy on your heat pump.
The best way to benefit from a heat pump’s superior efficiency is to use it for as much heating as it can handle. Experiment by opening a few doors to expand the zone, then turn up the fan. You might be surprised how much space a heat pump can heat.
5. DON’T use “AUTO” mode.
It’s natural to think “AUTO” mode would be a more efficient setting. But if you use it, your unit runs the risk of toggling unnecessarily between heating and cooling. Your heat pump will run most efficiently when set to “HEAT” in winter and “COOL” in summer. Note: “AUTO FAN” is a separate setting, and fine to use.
6. DON’T use the lowest fan speed.
Strange but true: a heat pump works most efficiently when set to a higher fan speed. Of course, high fan speeds can produce more ambient noise and air movement. Use the highest speed you’re comfortable with, then dial in your preferred temperature setting (see #1).
7. DON’T forget to keep up on maintenance.
This is true for almost any heating system. But that doesn’t make it any less important. It’s generally quick and easy to do. Consult your heat pump’s user manual for details on cleaning and replacing cartridges. Keep the outdoor compressor unit free of debris, snow, and ice. And hire a qualified professional to service your heat pump every year or two.
8. DON’T worry about an ideal swap-over point.
What’s a swap-over point? It’s the exact temperature below which it costs less to run your backup system than your heat pump. But it’s not easy to figure out, since it depends on backup fuel, heat pump model, electricity rates, and many other factors. Use your heat pump as much possible. Unless your backup heating fuel is a very affordable one, there aren’t enough super-cold hours in the year for your heat pump in cold weather to make a swap-over point worth worrying about.
— Efficiency Vermont