The short answer
The best ways to keep a Northern Virginia house warm this winter are mostly free: a clean filter, open registers, curtains working with the sun, and the drafts sealed. The things that cost people the most are habits, like closing vents, setting the thermostat to 85 and heating with the oven. Here’s the list we’d give a neighbor, and the things we’d tell them to stop doing.
What to do, free or close to it
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| Do this | Why it works |
|---|---|
| Check the filter every 30 days in heating season | A clogged filter starves the furnace of air, and it can shut itself off on its limit switch. Which filter to buy. |
| Clear every register and return | A couch on a return is a furnace breathing through a pillow. Leave a few inches of clear space. |
| Open curtains on the sunny side by day, close them all at night | The Department of Energy lists this as a free way to cut heat loss through windows. |
| Set ceiling fans to low, clockwise | It pushes warm air down off the ceiling. Which way your fan should spin. |
| Stop the drafts | Door sweeps, weatherstrip, foam gaskets behind outlets on outside walls, and the attic hatch. Hold a damp hand near each one on a windy day. |
| Keep humidity around 30 to 40 percent | Dry air feels colder at the same temperature. Water running down the windows means it’s too high. How to read your windows. |
| Clear the furnace’s white PVC vent pipes after snow | On a high-efficiency furnace, a buried vent shuts the heat off. Takes a minute with a broom. |
Free Furnace With a New AC
Put in a new AC with its matching coil and a basic single-stage gas furnace goes in with it, installed together. See the free furnace
Want your own number before anyone comes out? The HVAC estimator prices your house in a few questions.
What not to do
Don’t close vents to save money. Ducts aren’t a faucet. Your blower still moves the same air, now against more resistance. Rooms get uneven, and a furnace can overheat and trip off. If one room is the problem, there are real fixes for a cold room.
Don’t set the thermostat to 85 to warm up faster. It doesn’t. Heat comes out at the same rate either way. What to actually set it to.
Don’t heat with the oven or anything meant for outdoors. The CDC says never use a gas oven or stove for heat, and never run a generator or a charcoal grill inside or in the garage. That’s how carbon monoxide fills a house. Test your alarms now, and know what to do if one goes off.
Don’t flip a heat pump to emergency heat because it’s cold out. That setting runs only the expensive backup strips. It’s for when the outdoor unit has failed. Aux heat and emergency heat, explained.
Don’t wrap the outdoor unit. A heat pump works outside all winter and needs air through the coil. Frost that comes and goes is normal. A unit sealed in solid ice isn’t. How heat pumps handle a Virginia winter.
Don’t run a space heater like a furnace. The National Fire Protection Association says three feet from anything that burns, plugged straight into the wall, and off when you leave or go to bed. The rest of the space heater rules.
What not to do for your pipes
Don’t drop the heat overnight in a hard freeze. Don’t leave a hose on the spigot, because that’s how outdoor faucets burst inside the wall. Don’t ever put a torch on a frozen pipe. And don’t wait for an emergency to find your main shutoff: go find it today. We wrote a whole list on what not to do with frozen pipes, and another on keeping them from freezing.
Leaving town? That’s its own list: the thermostat and the water when you go away.
What our plumbers and HVAC technicians check first
Run the heat for a full hour on the first cold night, while you can still get an appointment. Here is the test. If it runs all day and can’t hold the temperature on the coldest days, here is why. If it’s blowing cold, start here. If there’s no heat at all, go through this before you call. The longer version of the fall list is our winterizing checklist, and this one is about the bill.
Book it
Everything on this list you can do yourself. Inside the furnace is the part you can’t. The heating check is $67 per system through December 31, on a furnace, heat pump or boiler. Book it from goswiftpro.com/cookiesoffer and free MOLTN cookies come with the visit. Or call (703) 997-9757. SwiftPro is rated 5.0 stars across 1,138 reviews on Google, Angi, Yelp, the BBB and Facebook, Virginia Class A license 2705192276.
Questions people ask
What’s the best way to keep a house warm in winter without spending money?
Change the filter, open the curtains on the sunny side during the day, close them all at night, move furniture off the registers, and set the ceiling fan to low and clockwise. All of it costs nothing or close to it.
Does closing vents in unused rooms save money?
No. The blower pushes the same air against more resistance, and a furnace can overheat and shut itself off. Leave them open.
Does setting the thermostat higher heat the house faster?
No. The system puts out heat at the same rate whether you set 70 or 85. A higher number only means it runs longer and overshoots.
Should I cover my outdoor unit in winter?
Never wrap a heat pump: it runs all winter and needs air through the coil. Keep snow cleared at least a foot or two around it.
