Up, up and not away!

This is not technical, but opinions after living with radiant floors for several years: One thing to remember is that we must adapt to a difference in how we think about heating. With F/A, wood, radiators, etc. we have a tendency to look at the outside thermometer registering cold, and then turn up the inside thermostat. Or maybe we walk by a window and feel cold seeping in -- and turn up the thermostat to compensate. That's often habit, but the habit is based on the fact that most houses are/were poorly insulated and often let cold or drafts into the living area -- so if it's cold outside our subconscious says oooh, it's gonna get cold in here, turn up the heat. You almost have to live with radiant flooring to really realize that one just doesn't need to play with the thermostat. If your house is well-insulated (and to an amazing extent even if it's not well-insulated) you set the thermostat for the temperature at which you are comfortable, regardless of what's going outside and you leave it there. And another thing which is rarely addressed is the fact that many (most?) people set the radiant flooring to 75 and are on the warm side of comfortable regardless of whether or not it's frigid outside. No matter what your source of heat, it takes less energy [and less $] for 75 than for 80°. Yes, if the cat stands in an open door peering out at a snowstorm there will be frigid draft coming in... no matter whether you have F/A or radiant. The difference is that F/A will have to warm up that cold air with more not-very-warm air and meanwhile you have both cold and F/A warm air blowing around you. Brrrr. With radiant, you have --and keep-- warm feet which physiologically makes you feel warm because the temperature of the floor has not changed. Yes, the open door's cold air is mixing with the warm air but it isn't blowing onto you to make you feel cold. Talking about vacations -- or a length of time away from home -- should take into consideration that radiant flooring does not make any ultra-high demands on its system. Radiant is meant to *maintain* an even temperature, not jerk it up with a blast of heat like other heating methods. So it makes sense to turn off a furnace while you aren't home because a furnace requires a blast of heat to warm the volume of air; long blasts for lots of warmth and short blasts when there isn't much difference between ambiant and desired air temps. Unless you are going to be gone for lots longer than it takes to cool-off followed by heating-up the radiant flooring, it does not make sense to change its temperature. Modern houses with radiant flooring are almost always considerably better insulated than their F/A counterparts, and it takes days not hours to cool off. And last, there are often comments about the length of time it takes to "warm up the house" with radiant heat. Especially if one lives in an area with a great variety of temperatures. Ah, excuse me, but if I'm comfortable at 75° what difference does it make what the temperature is outside??? If the house is highly insulated and draft-free it makes very little difference whether it's 10° or 50° outside. In my area outside temperatures with daily 40-degree variations are common for weeks at a time, regardless of season. Okay, not so common in the summer, but we don't need heated houses in August. On the rare occasion that it gets umcomfortably warm inside, I open the window. Low-tech but effective. Oh yeah, in July and August I turn on the A/C, not so low-tech, but effective. The point is, 75 is 75 is 75 and if your feet are happy at 75 it doesn't matter what temperature the outside air is. A 'warm house' is a side-effect of radiant because its main purpose is keep you comfortable, that is, maintaining your comfort with an even temperature.

Hello; I don't know what you should or shouldn't use but here is what I did! We took over (bought) on a log cabin being built in the Lake Tahoe area and I did a little research & I went with hydroic floor heating system. What was so neat was when you walked in, the house was just unblievably warm. No dust, no fan , nothing! Our cabin was 2,000 sq ft with 4 heating zones (2-bedrooms, loft, & kitchen/nook/greatroom combo. We placed a thermostate in each zone so that we could not heat each zone independently as needed. I did do some of the work myself like cutting up the 1,000 ft roll rubber hose to 4ea. 250' sections so that I could run them in a continuous form with out any joints except at the boiler (No Leaks). I started every run with a loop through the bathroom then along the out side walls and into the center until my half way mark was secured to the floor then i reversed back to the boiler. I did this to each area & then ordered light weight concrete & had it pumped in over the floors to 1-1/2" thickness to cover the piping. I ran plastic, cardboard, & then my hardwood (glue together, NO nails) flooring for great looking floor that was warm to your feet on a cold night. I also used a non-conventional water heater that a line from the boiler runs though or around the outside walls (separate from your house hold water) that heated the water, & we also installed a 1/4 h.p. motor on a circulating line that saved us from having to wait for the water to get hot to take a shower. Because I was in an area that I didn't need A/C help make this a player for me & I absolutely loved the system that cost us an extra 20% over forced air system, but this was in the early 90's, so I'm not up to speed on whats available now. That system is now 15+ years old and still working well! Elden

dovetonsils, I could be off on my balance point estimate. Whether it is 35-40, or 20-25 (seems very low for a conventional heat pump), it is going to be dependent on a lot of variables. There are two balance points. One is the point where it is more economical to use the heat pump versus the back up heat system. If the back up is resistance heat, then I agree with you it is towards your range. If you are using propane, then it should be at the higher range. If the cost of propane goes up, then the balance point can be changed. I happen to think we are going through a long period of low natural gas and propane prices, but that is just my opinion. The other balance point is the temperature at which the heat loss of the house is greater than the heat provided by the heat pump. Usually that is higher than the economical cross over, but again it is highly dependent on the specific house and heat pump performance. It seems to me air handlers cost about the same as a furnaces assuming they have similar features. Even if the furnace is a little more expensive, the OP will come out ahead if the difference is less than the additional required electrical work. The furnace blower will be used every time the heat pump operates. The part that will be used less often is the gas valve and burner. Not much maintenance to be done. Every 2-3 years should be fine. It will also mean less wear and tear on the heat pump. The other nice thing about having the furnace is that if the heat pump fails, you can heat the house with no problem while you wait for service. It is no fun servicing a heat pump in the middle of a winter storm. I think the OP should get quotes for both options as part of the decision making process. Either option is viable and will work.