What is radiant heat?
DEAR TIM: I’m looking to buy a house, and I’ve seen online descriptions saying a house has radiant heat. What in the world is that? The house I grew up in had hot air that blasted out of ducts. What are the pros and cons of radiant heating? Is it expensive to operate? Would you own a home with radiant heat? --Lucy B., Goochville, Va.
DEAR LUCY: Radiant heat is by no means new. It’s as old as our solar system. When you go outdoors on a sunny late-winter morning and feel the warmth of the sun when it’s invisible infrared rays hit you, that’s the oldest and most basic form of radiant heating. It’s time tested, and in my opinion, the best form of heating you can have.
Radiant heat uses invisible electromagnetic infrared waves to heat you. It doesn’t heat the air, as the system did in the house you grew up in. The objects that are in the direct pathway of the infrared rays absorb the energy immediately. Once they heat up, they radiate heat to other objects in the room. It’s a fascinating way to transfer heat very efficiently.
Radiant heat sources in a home can take many forms. A simple fire in a fireplace produces radiant heat, as does a fireplace insert, a woodstove, portable electric heaters, electric quartz heaters, radiators connected to a central boiler, and so forth.
My own home has radiant heat and it’s luxurious. The finished basement has radiant tubing that snakes through the concrete slab. The entire basement floor becomes a giant radiant panel that heats everyone and everything in the space. Walking in bare feet or laying on the floor is pure ecstasy. I have baseboard radiators in all the other rooms of the house.
There are many pros and few cons, in my opinion, when it comes to radiant heating. As for the pros, here are a few. It’s nearly silent, it’s clean, it’s comfortable, there are no ducts to clean, it’s efficient and requires minimal maintenance.
A major benefit in my opinion is the ability to zone your house. With a small amount of effort and some additional expense, you can have groups of rooms on their own zone. This allows you to have different zones at different temperatures at different times. If you only use a few rooms in your home, you just can heat those rooms in that zone.
The only cons I can think of are it might be a little more expensive to install and some people find the baseboard radiators unsightly.
You don’t have to install wall or baseboard radiators. People choose them as that’s almost always the cheaper alternative. It’s possible to have a radiant heating system totally invisible with all the piping hidden in floors or ceilings.
The cost to operate a radiant heating system that uses a central boiler and one or more recirculating pumps can be minimal. Even with this in mind it’s a very hard question to answer because there are many types of radiant heating systems and each one might have a different fuel source.
One type of fuel may cost much more per Btu of heat produced than another. For example, you may live in an area where electricity is insanely cheap and the cost of propane is outrageous, while I may live in an area where fuel oil is the best buy per Btu. Always compare fuel prices based on Btu of heat output. A good way to do that is to figure out what it costs to generate 10,000 Btus using each type of fuel.
Keep in mind that your house may be much different than other houses in your neighborhood. The Btu heat loss of your house is a function of its size, insulation, window and door openinngs, compass direction it faces, etc. Each house has a distince Btu heat loss per hour. To keep a house comfortable, you must replace the lost Btus with new ones each hour.
If you want low heating costs, you need to make sure your Btu heat loss is low and the efficiency of the heating device is very high. High efficiency means that almost all of the heat produced when burning the fuel remains in your home instead of going up a chimney. Modern boilers are in the 90 percent-plus efficiency range.
SIDEBAR
Radiant heat can be installed in an existing home, but it can be very expensive. It’s probably best to use wall radiators that deliver exceptional results.
In new construction, a heating contractor can install the plastic piping that delivers hot water to each of the rooms in little time. The wise homeowner plans ahead so that the rooms that are not used that often are zoned together. Rooms that are frequently used at the same time are put on just one zone so that fuel usage is minimal.
You can watch a very fascinating radiant heat video that shows new radiant heat transfer plates at www.AsktheBulider.com. Just type “radiant heat transfer plate video” into the AsktheBuilder.com search engine.
(Want free home-improvement information? Go to www.AsktheBuilder.com and sign up for Tim’s free newsletter. Have a question for Tim? Just click the Ask Tim link on any page of the website.)
