In doing research for how to heat our basement, we came across some interesting facts. Surprisingly enough, basements don't lose a lot of heat But why do they then often feel dark and cold? The reason behind that 'basement feeling' is because basements are not heated at all (older basements not originally intended for living space) and because any cold air from the house tends to sink down to the lowest level. Adding heat to the basement doesn't have to be very hard. We found quite a few options that we carefully weighed before deciding on the perfect fit for our house. But since there are so many varying factors to each house, here are some facts for you to decide for yourself.
What kind of heat?
There are a few different ways to heat your basement. Some of them are cheap and easy to install, some of them are really complicated. Some of them are cheap to run and some of them cost an arm and a leg. Here's the break down.
Cost to install: Low :: Cost to run: High
Electric heat comes in the form of electric baseboards or wall space heaters. It can also come in the form of portable heaters plugged into wall receptacles but those usually can't be controlled by a thermostat and should only be used if you won't be using your basement on a regular basis. The amount of heat you get from electric heat is directly dependent on the wattage. On a 15 amp circuit at 120 volts you can use up to 1440 Watts per circuit, on a 20 amp circuit at 120 volts you can use up to 1920 watts. Electric heaters often run on 240 volt circuits and can have up to 2880 watts at 15 amps or 3840 at 20 amps. It's pretty cheap to run wires to the heaters, the only concern would be running out of circuits on your main panel. The biggest drawback to electric heat is that it's the highest cost to run.
Hydronic Electric Baseboard heaters are electric heaters that heat up a liquid to disburse the heat. They stay warm longer which can be confusing because they also take more energy to heat up. 1 watt of electricity makes a certain amount of heat (3.413 BTU/hr to be exact) whether it's a normal baseboard heater or a hydronic baseboard heater which means it will take the same amount of electricity for either options and cost the same amount to run. You can use either one but there's no reason to spend more for one or the other when they do the exact same thing.
Cost to install: Medium :: cost to run: Low
If you have forced air heat throughout your house your best bet is to run some new air ducts to your basement rooms. You'll just have to make sure your furnace can handle the extra capacity. It will cost a little bit to install but it won't cost much to run the furnace on natural gas. Most newer houses run on forced air with heating vents. Since ours doesn't, we honestly didn't do too much research here.
Cost to install: Medium :: cost to run: low
Hot water can run through radiators (expensive) or baseboard heaters (inexpensive). The baseboard heaters look a lot like electric baseboard heaters but inside hot water heats up the tubes instead of using electricity. Radiators and baseboard heaters can run off an existing boiler with a zone valve so they can run at different times than the rest of the house. The existing boiler must have enough capacity to add another zone. The zone valve and plumbing cost a bit to install but the boiler won't cost a lot to run in the winter.
In Floor Heat
Cost to install: High :: cost to run: depends
In floor heating works by running hot water through tubes in the concrete slab (called hydronic in floor heating). The water heats up the concrete and the concrete radiates heat all day long. In-floor heating is the number one choice for heating a basement. In-floor heating can also be created by installing electric mats (called electric in floor heating), a lot like an electric blanket, that are installed right below your flooring. It gets rid of any cold floors and feels great to walk on.
Electric in-floor heating is fairly expensive and has the same pit fall of electric heating - it costs a lot to run. Hydronic in-floor heating is the most expensive to install, especially if you're trying to retrofit it into a basement. If you're building a new house this is hands down the best way to go. If you're renovating a basement there are a few options - 1) Tear up the foundation slab and pour a new one with in-floor heating installed; 2) Pour concrete over the existing slab with in-floor heating installed; 3) Install a "dry" in-floor heating where the heating tubes are installed in a wood sub floor instead of concrete. Option 1 is out of most people's price range, option 2 takes up valuable floor to ceiling height (this might not be a problem if you have 8 or 9 foot ceilings in the basement) and option 3 is far less efficient because wood doesn't radiate heat as well as concrete.
Regardless of cost or inefficiency, in floor heating will feel the best. We looked into the cost and decided against it but we definitely recommend finding out the cost for yourself and deciding from there. Because our boiler has the potential capacity to add another zone, because we really like our radiant heat thus far for warmth and economical purposes, we've 90% decided on adding radiant heat to warm up our basement.
How much heat
Once you've decided which kind of heat to use, you'll have to decide how much heat you'll need. Heat travels from warm areas to cold areas so your basement isn't cold because cold air comes in, it's cold because hot air escapes through leaks in windows or by escaping through walls. The amount of heat your basement loses is called Heat Loss and it's measured in BTU/hr. To keep your basement toasty you'll need to add heat at the same rate you loose heat. There are online calculators to help you figure out how much Heat Loss your basement is producing. You can also check out a really informative post on heat loss from Robin at 3 acres & 3 thousand sqft - she works in HVAC and knows what she's talking about!
Surprisingly, basements don't lose that much heat, especially basements that are all below ground (walkouts lose more heat) and ones that are well insulated. In the winter the outside air is colder than the ground (especially in cold states) so below ground walls are actually warmer than above ground walls. Also there are fewer places for the warm air to escape since most basements have smaller windows and only one exit.
Our 1,000 sqft basement had a heat loss of around 5,000 BTU/hr. Our main level has a heat loss of around 40,000 BTU/hr to put the heating loss into perspective! We're going to have a lot of insulation in the basement which also dramatically lowers the heat loss.
Once you know your heat loss you can calculate how much heat you'll need. For example, I mentioned earlier that 1 watt of electricity produces 3.413 BT/hr so our basement would need 1,465 watts of electricity (5,000 / 3.413 = 1465) to heat it enough to counteract the heating loss. We chose to install hot water heating though, which isn't measured in watts. 1 foot of a baseboard hot water heater produces about 500 BTU/hr so we need a total of 10 feet of baseboard heat (5,000/500 = 10). Simple enough?
Pay now or pay later
The moral of the story here is that there are ways to heat a basement that don't cost a lot up front - electric heat with no insulation - but these will cost a lot to run in following years. There are more expensive heating methods and insulation that cost a bit now but will save money down the road. We looked at the difference between electric and hot water heat. Hot water heat will cost around $700 more to install but will be around $300 per year cheaper to run. We'll recoup our cost after just over 2 years and then save $300 each winter every year after.
Hopefully this takes some of the mystery out of choosing a heating system. And if you're not in the place right now where you have to make this choice, you've hopefully gained a better understanding of how houses are heated and why/how we've made the heating choice for our basement renovation!