CoolPlain

Bare glass versus the same window with a taped film: about half the heat loss. Hold your hand near a bare window on a cold night and you can feel the heat leaving the room. The fix is cheaper than almost anything else in home energy: a clear plastic film kit, taped to the window frame and shrunk tight with a hair dryer. On a single-pane window it cuts the heat flowing out through the glass by about half. On a double-pane window, by about a third. Glass is not the insulator. The air is. This is the part that surprises people. A pane of glass barely slows heat at all. Almost all of a bare window's insulating value comes from the thin layer of still air that clings to each side of the glass. Those two air layers do the work. The glass just holds them apart. A film kit adds a second pocket of trapped air, about an inch (2.5 cm) deep, between the film and the glass. That pocket resists heat about as well as the two air layers combined. So the window ends up with roughly double the...

Price change since January 2020 as stated in the class-action complaint: HVAC equipment, kitchen appliances, and prices in general. Seven companies that make most of the air conditioners, furnaces and heat pumps sold in the United States are being sued for fixing prices. On October 9 they asked a federal judge in Michigan to throw the case out. Here is the short version. Nothing in the case changes what you should do this fall, and the biggest savings on a new system still come from the quotes you collect, not from a courtroom. What the lawsuit says, and what the makers say back The suits were filed this spring by homeowners and by contractors. They name Carrier, Trane, Lennox, Daikin, Rheem, Bosch and AAON, which between them sell most of the heating and cooling equipment in the country. The claim is simple: since 2020 these companies raised prices in step with each other, by more than their costs went up, and signaled their plans to one another through public announcements an...

A winter that runs 1 °F warmer uses about 6% less heating fuel. One hard cold week can give most of that back. NOAA's winter outlook came out last week, and for most of the northern half of the country the headline is a warmer-than-average winter, pushed by one of the strongest El Niños on record. So yes, if that holds, you will burn less fuel. But less is not zero, and the forecast is a tilt of the odds, not a promise. The useful question is what a warm winter is actually worth to your house, and what to do about the cold weeks that still come. Your furnace counts degree days, not forecasts Your heating system does not care about the season's average. It cares about every single day, and how far below about 65 °F (18 °C) that day sits. Utilities call that gap a degree day: the colder the day, the more degree days it adds, and the more heat your house asks for. Think of a bucket with a hole in it. The colder it is outside, the bigger the hole, and your furnace or heat pump i...

Two timelines: a healthy furnace runs in one long stretch of 10 to 15 minutes; a short-cycling furnace runs in three-minute bursts with gaps between  A healthy furnace runs long and rests long. Short cycling is many short burns an hour. The furnace lights, runs a few minutes, shuts off, and a little later does it again. All evening. That stop-and-start pattern is called short cycling, and most of the time it begins with air, not with the burner. Pull the filter first. If a fresh one does not fix it, the furnace is probably too big for the house, or the thermostat is sitting in the wrong spot. What a healthy cycle looks like A furnace is built to run in long, steady stretches. On a cold evening it comes on, runs 10 to 15 minutes or more, and stops when the thermostat is satisfied. Short cycling means it keeps quitting after a few minutes, over and over, often before the house is warm. Inside, a safety switch watches how hot the metal gets where the air picks up heat. It counts ...

One radiator stays lukewarm while the rest of the house is cozy. Or it is hot along the bottom and cool across the top, and you hear a little gurgle when the heat kicks on. In a hot-water heating system, that almost always means a pocket of air is sitting where hot water should be. Letting it out takes a few minutes and a tool that fits in your pocket. Why a bubble can beat a boiler About 9 million US homes heat with a boiler. It warms water, and a small pump pushes that water through pipes to the radiators or baseboards in each room and back again. The loop is supposed to be completely full of water. Air gets in anyway. Fresh water carries dissolved air, the same way a cold glass of tap water grows tiny bubbles as it sits on the counter. Heat the water and that air comes out. The bubbles drift upward and collect at the high spots, which usually means the tops of the radiators, and most often the ones upstairs. Air is light and the pump is gentle. It was sized to keep water circul...

The water heater's job in July versus January: the same 105°F shower needs a 35°F lift in summer and a 60°F lift in winter. Same tank, same shower, same family. Then January arrives and the hot water quits five minutes early, and whoever showers second gets lukewarm. Nothing is broken. The water coming into your house is a lot colder in winter, and your water heater has to lift every gallon almost twice as far. Here is what is going on, and how to get those minutes back. The cold is in the pipe under the street Water reaches your house through a pipe buried a few feet down, and the ground there follows the seasons slowly. In the northern states it bottoms out around 40°F in late winter, in the South around 50°F, and by late summer it runs 20 to 25 degrees warmer than that. During a hard cold snap I have seen incoming water in the mid-30s. A comfortable shower is about 105°F (41°C). In July the heater lifts the water 35 degrees to get there. In January it has to lift it 6...

Adding up what runs at once: the heat pump fits the panel, the 10 kW backup heater does not. Ask about a heat pump and somebody will tell you that your 100-amp panel has to go first. Usually it does not. If your house already has central air conditioning, the heat pump itself almost always fits the panel you have. What does not always fit is the electric backup heater that gets installed next to it. The heat pump is the easy part A heat pump is an air conditioner that can run backwards. In summer it moves heat out of the house, in winter it moves heat in. The outdoor unit draws about the same power as the air conditioner it replaces, and it plugs into the same 240-volt circuit. Newer inverter models often draw less at start-up, because they ramp up gently instead of slamming on. Your electrical panel is like the main water pipe into your house. It does not care how many faucets you own. It only cares how many are running at the same time. That is why the backup heater matters. On the c...

Day 70°F, night 62°F: about 7 percent less heating on a cold night. You have probably heard both versions: turning the heat down at night saves money, and turning it down costs more because the furnace has to "catch up" in the morning. The first one is right. A cooler house loses heat more slowly, and the furnace never has to pay back more than the house lost. Set it back 8 degrees for 8 hours and a gas furnace burns about 7 percent less on a cold night. Own a heat pump? Read the part about backup heat before you touch the schedule. Why a cooler house is a cheaper house A house leaks heat all the time, through walls, windows, the roof, and every little gap. How fast it leaks depends on one thing: the difference between inside and outside. Drop the inside from 70 to 62 on a 30 degree night and the gap shrinks from 40 degrees to 32, so the leak slows by a fifth. Think of a bucket with a hole in it. The higher you keep the water, the faster it runs out, and the more you have to ...