Too often building professionals, architects, general contractors and even HVAC contractors, seem to give minimal consideration to the comfort of the people living in the home. We see many beautiful homes with terrific views and uncomfortable occupants.
Consider this. Humans are living radiators. Our bodies want to radiate heat at a specific rate. If we radiate heat too fast, we’re cold. Too slowly and we’re hot. Think back to a summer grocery store trip wearing shorts and a short sleeve shirt. You are comfortable in the canned goods aisle, but have goose bumps in the freezer aisle. Why is that when the air temperature is the same?
It happens because the temperature of the canned goods is close to room temperature; on the other hand, those glass freezer doors in the frozen food aisle are much colder than those canned goods, causing our bodies to radiate heat faster and making us feel chilly.
The same thing happens in homes. Those beautiful wood frame double pane picture windows with the great view will make you feel chilly sitting next to them on a cold winter night. This is because we have two main factors at work. The “faster than our bodies want” radiant loss mentioned above, but we also have a cold air “waterfall” flowing off the glass that can make our feet cold as well.
Radiant floors will help the keep our feet warmer and us more comfortable, but it doesn’t really address the radiant loss a person feels if they’re within a few feet of a cold surface like a window.
The best solution we’ve found is the use of European style panel radiators located under cold surfaces like windows. This allows both a convective “curtain” in front of the cold surface, as heat from the radiator rises across the window, and direct radiation to help keep the people comfortable. The best implementation is panel radiators coupled with a low temperature modulating boiler, constant circulation and an outdoor reset control.
The only concern we have now is how to prevent “thermal overshoot”. Occasions when the room temperature exceeds the temperature we’d like it to be. Think a sunny, but cold winter day with a south facing living room and lots of glass for those great views. Heat is being added to the home based on the outdoor temperature, but we’re also getting a lot of solar gain in areas as well. To counter this, the panel radiator’s thermostatic valves will sense the increase in room temperature and reduce the volume of water flowing through the panels, thus reducing that radiator’s heat output. The valves are adjustable and in effect give room by room temperature control. Have a seldom used guest bedroom? Dial the radiator valve down. Want a room a little warmer? Dial the valve up a bit.
Panel radiators lend themselves to the use of more efficient boilers and circulator pumps. Higher efficiency boilers will save the most money when the system water is cooler. The cooler, the more money saved. Unlike baseboard we can design a panel radiator system to operate at much lower temperatures while still maintaining great comfort. To get a lower system water temperature we use a little larger radiator. Since panel radiators are available in a great variety of heights, widths and thicknesses, it’s usually fairly easy to find a good match for the space. Variable speed circulating pumps use about ¼ to ½ of the electricity used by standard circulators saving you more money when you consider these pumps run for thousands of hours a year.
If you have a beautiful home with lots of glass or uncomfortable areas in your home, consider panel radiators for the comfort and savings they offer.