How to Keep Your House Warm in Winter Without Cranking Up the Heat: 15 Tips
Wondering how to keep your house warm in winter without a shock on your next PG&E bill? San Jose winters are mild by East Coast standards, but nights regularly drop into the 30s and 40s, and many Bay Area homes lose heat fast through single-pane windows, uninsulated attics and drafty doors. The usual reaction is to crank up the thermostat, which only makes the furnace run longer and the bill grow.
In fact, to keep your home warm without raising the thermostat, you should take a smart, comprehensive approach: eliminate drafts, arrange furniture and curtains properly, and use your heating equipment correctly. Experts from Freon Service share 15 practical and budget-friendly tips to help you keep your home warm without overheating your gas furnace.
Why Your House Loses Heat (and Why Cranking the Thermostat Won’t Help)
Before you try to prevent drafts from entering your home, you should understand the main cause of the problem. The physics behind it is simple: thermal energy always flows from a warm room to the cold outdoors in three ways:
- Conduction: Heat escapes directly through solid materials-glass without double-pane windows, walls without insulation, and bare floors.
- Convection: Warm air rises and escapes through gaps in windows, doors, attic hatches, and light fixtures.
- Radiation: Heat radiation from the human body and objects “escapes” toward cold surfaces (for example, toward large windows).
| Heat Loss Zone | Typical Impact | How Heat Escapes |
| Attic and Roof | High | Warm air rises through convection and escapes through an uninsulated ceiling or hatch. |
| Windows and Doors | High | Drafts through gaps in frames, under-door leaks, and direct conduction through glass panes. |
| Walls and Outlets | Medium | Uninsulated wall cavities, electrical switch boxes on exterior walls, and structural gaps. |
| Floors and Crawl Space | Medium | Cold air infiltration from an uninsulated crawl space or basement chills the flooring. |
A Common Misconception About Thermostats: Many people think that setting the thermostat to 75°F instead of 68°F will make the furnace heat the room faster. However, that’s not how it works. A furnace or heat pump always delivers air at a constant temperature. Turning the thermostat up to the maximum doesn’t speed up the heating process; it simply forces the system to run much longer, nonstop, causing it to wear out faster.
How to Keep Heat in the House: Stop Drafts and Insulate
The best and most affordable way to stay warm is to keep the heat that has built up inside your home from escaping.
1. Seal Air Leaks Around Doors, Windows and Outlets
Apply self-adhesive weatherstripping to the window frames and install rubber thresholds at the bottom of the entry doors. Be sure to place inexpensive foam gaskets under the plastic covers of electrical outlets and light switches on exterior walls. Experience shows that these are among the main causes of drafts.
2. Add Insulation to the Attic and Crawl Space
Since warm air rises, an uninsulated attic can account for up to a quarter of all heat loss. Adding mineral wool or insulation to the attic (to a R-value of 38–60) will create a reliable protective barrier. In addition, you should block the cold air coming up from the crawlspace under your house.
3. Do Curtains Keep a House Warmer? Use Thermal Curtains
Using warm, lined thermal curtains will create an air cushion between the cold glass and the room. If you close them in the evenings, this will help you retain heat in the room, and the room will stay noticeably warmer through the night.
4. Will New Windows Keep Your House Warmer? Try Window Film First
Replacing windows with new double-pane ones is a fairly expensive investment. If your home has old wooden or aluminum single-pane windows, apply a clear heat-shrinkable film to them using a regular hair dryer. It creates an insulating air chamber and will save you money.
Use Free Heat: Sunlight, Fans, Rugs and Your Kitchen
The easiest way to make your home warmer is to use heat sources you already have.
5. Open South-Facing Curtains During the Day
On sunny and winter days in San Jose, open the curtains on your south- and west-facing windows. The sunlight will provide a free source of heat for your walls, furniture, and floors.
6. Run Ceiling Fans Clockwise on Low
During cold weather, the ceiling fan should be switched to winter mode. In this mode, the fan rotates clockwise at the lowest speed. This prevents the fan from blowing cold air downward; instead, it gently circulates the warm air that has accumulated near the ceiling back down toward the floor.
7. Do Rugs and Carpets Keep Your House Warmer?
Do carpets keep your house warmer? Yes — plush rugs and runners insulate cold hardwood, laminate and tile floors. One of the best ways to retain heat is to use plush rugs or runners. A rug serves as an excellent insulator for particularly cold surfaces, such as hardwood floors, laminate, and tile.
8. Does a Humidifier Help Keep the House Warm?
Moist air feels warmer than dry air at the same temperature. Keeping indoor humidity at 30–50% makes 68°F feel noticeably more comfortable, so you won’t be tempted to raise the thermostat.
9. Let Heat from Cooking Stay Inside
After cooking a meal in the oven, turn it off and leave the door slightly ajar so that the residual heat can warm your home.
Warning: Never use a gas stove or oven to heat a room! This poses a deadly risk of carbon monoxide poisoning. Make sure your CO detectors work: California requires them in every home with a gas appliance or attached garage.
Use Your Thermostat and HVAC System Smarter
Smart and optimal automation settings will help you save money without sacrificing comfort.
10. How Warm Should You Keep Your House in Winter?
The U.S. Department of Energy (DOE) strongly recommends setting your thermostat to 68°F (about 20°C) when you are at home and awake. If you lower the temperature by 7–10°F for 8 hours a day while you sleep or are at work, you can save up to 10% a year on your heating bills.
11. Preheat Before PG&E Peak Hours
PG&E time-of-use electricity rates are highest from 4 to 9 p.m. If you heat with a heat pump or electric heaters, warm the house to 70°F before 4 p.m. and set it back to 65°F during peak hours. The heat stored in walls and furniture will carry you through the most expensive part of the day. Gas furnace heating isn’t billed by time of use, so this tip matters most for electric heating.
12. Program a Smart Thermostat Schedule
To save you time and energy, installing a programmable or smart thermostat (such as Nest) is an excellent option. It will be a real help to you. These devices will automatically lower the temperature at night and before you leave the house, and will start heating the house again by the time you return.
13. Heat Only the Rooms You Use (Zone Heating)
To avoid heating rooms you rarely use, partially close the vents there, but keep at least 80% of the vents in the house open: closing too many raises duct pressure and strains the blower. For an evening in one room, a space heater with tip-over and overheat protection gives localized heat.
14. Keep Vents Clear and Change the Air Filter
Replace the air filter regularly. A clogged filter will prevent proper air circulation, causing the furnace to run inefficiently.
15. Close the Fireplace Damper When It’s Not in Use
An open fireplace damper acts like an open window, drawing all the warm air out of the house and into the chimney. Always close the damper tightly when you are not using the fireplace.
How to Keep an Old or Poorly Insulated House Warm
Learning how to keep an old house warm in winter takes a slightly different approach.
Eichler and Mid-Century Homes in San Jose
Famous Eichler-style houses, with their flat roofs and panoramic windows, look beautiful and aesthetically pleasing, but they tend to lose heat quickly:
- Glass walls: Cover them with thick thermal curtains or use protective films.
- No attic: Because of their flat roofs, these houses have no attic space, so the roof itself must be insulated during renovations.
- Radiant floor heating: Older radiant floor systems take a long time to heat up. They are perfectly complemented by modern zone-based heat pumps (mini-splits).
Two-Story Homes and a Cold Lower Level
In two-story homes, heat always rises to the second floor, leaving the first floor cold. To balance the temperature, slightly close the dampers on the second-floor vents, causing the system to direct more air downward.
Cheapest Ways to Keep Your House Warm: Cost vs Impact
Here are the cheapest ways to keep house warm in winter, from free fixes to professional upgrades:
| Method to Keep House Warm | Estimated Cost | Heat Retention Impact | Who Performs It |
| Switching Ceiling Fan to Clockwise (Winter Mode) | $0 | Moderate | DIY |
| Opening South-Facing Curtains During the Day | $0 | Moderate | DIY |
| Closing the Fireplace Damper | $0 | High | DIY |
| Setting a Nighttime Thermostat Schedule | $0 | Very High | DIY |
| Replacing the Air Filter | $10 – $25 | Moderate | DIY |
| Installing Outlet Gaskets and Door Weatherstripping | $15 – $40 | High | DIY |
| Applying Window Shrink Film (Window Film) | $20 – $50 | High | DIY |
| Hanging Thermal Insulated Curtains | $40 – $150 | Moderate | DIY |
| Installing a Smart Thermostat | $120 – $250 | Very High | DIY / Professional |
| Attic and Crawl Space Insulation | $1,200 – $3,500+ | Maximum | Professional |
When Your Furnace or Heat Pump Can’t Keep the House Warm
If you’ve sealed the cracks but the furnace still can’t fully heat the house, then the problem lies with the furnace itself.
Signs Your Furnace Is Struggling to Keep Up
If your gas furnace has been running continuously for hours but the temperature isn’t reaching a certain level, or if only lukewarm air is coming out of the vents, it’s time to call a repair technician. The problem could be caused by dirty burners, a faulty gas valve, or a broken fan.
Heat Pump Not Keeping the House Warm?
Short defrost cycles, when the unit briefly blows cooler air, are normal. But if it blows cold air for long periods, the refrigerant may be leaking or the outdoor unit may be blocked by leaves and debris.
What to Do If Your Furnace Breaks in Winter
If the heat goes out during a cold snap:
- Check the batteries in the thermostat and the circuit breaker panel.
- Check the filter: a completely clogged filter can make the furnace overheat and trip its high-limit switch.
- Gather your family in the warmest room and turn on a safe space heater.
- Call an emergency HVAC repair service.
Keeping Your House Warm FAQ
Does it cost more to keep your house warmer?
Yes. The higher the temperature inside the house compared to outside, the faster the heat will escape. That is precisely why the furnace runs longer, and gas and electricity bills go up.
Is it cheaper to leave the heat on all day?
Usually not. A house loses heat faster the warmer it is inside, so keeping it fully heated while nobody is home wastes energy. Setting the thermostat back 7–10°F while you’re away or asleep saves more, and a programmable thermostat can warm the house again before you return.
What temperature should you set your thermostat at night?
Most people sleep best at 60–67°F, and the U.S. Department of Energy suggests setting the thermostat back 7–10°F at night. Under a warm blanket, this saves energy without losing comfort.
Do space heaters save money?
Only if you’re heating one specific room while turning off the heat in the rest of the house. If you turn on several space heaters throughout the house, it will end up costing significantly more than running a gas furnace. Using multiple electric space heaters will lead to higher utility bills.
Will a heat pump keep my house warm in winter?
Yes, that’s true. In San Jose’s mild climate, modern heat pumps operate at high efficiency and easily keep homes warm while using minimal electricity.
Stay Warm This Winter with Freon Service
Keeping your home warm in the winter without breaking the bank on PG&E bills is both realistic and affordable. Combining simple heat-saving methods with effective and proper thermostat settings is the most cost-effective, comprehensive approach.
And if your gas furnace or heat pump is running erratically, breaking down regularly, making strange noises, or failing to heat your home, the experts at Freon Service can help with professional, high-quality diagnostics, cleaning, and tuning of your equipment. Schedule a service call right now so you can stay warm and cozy this winter!
Members of the Freon Service HVAC membership get an annual furnace tune-up and priority scheduling during cold snaps.
