True efficiency?

hr

there have been a number of studies done to pin down that number. All contested by the loser :)

If both systems were properly installed and insulated, and if both had high efficiency equipment with outdoor reset, I doubt that the difference would be as high as you suggested.

While the comfort, and zone-ability of radiant is unsurpassed, in my opinion, FA would be better able to handle cooling and IAQ.

IAQ being very important in tight "foam block" homes that are getting more and more common.

I say hybrid systems are the way to go. Have some air handling equipment to cool humidify, filter, and treat incoming air. Then warm floors in critical areas, baths, kitchens, sitting areas, etc.

hot rod

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Simply Rad_2

True efficiency?

I have had this question alot lately and looking for some numbers to give customers. I have programs that estimate fuel cost usage but none compare radiant to forced air. What are the true savings of radiant floor heating using a modualating, outdoor reset, 95% condensing appliance radiant system VS a forced air system.
What I have been seeing is 30-40%.
Thanks Jeffrey

Simply Rad_2

Radiantville

Most of the systems I have been working with are all radiant. Here at 7000' in colorado we are heating dominant. Cooling-just open the wind at night and close the windows during the day. Last night for the forth of July fireworks I was cold in shorts by the end. Our low last night was 42 degrees. I find that most people want radiant everywhere. It is truly "radiantville" 95% of all new builds are radiant. I have been getting into indoor air quality with ERV's and I want to look into humidification systems. Another big difference between MO and Colorado is the humidity. Right now we are at 21% humidity compared to you at 80% I remember those days of hot sticky nights, all hudled in the family room because that was where the air conditioner was. I grew up in Ohio-90 degrees and 90% humidity.
Thanks Jeffrey

Steamhead

I've seen some posts here

suggesting that heat loss from ducts averages 20%. Don't know where that figure came from, or if it also applies to cooling, but especially if it's not the "worst case" it would seem to make a pretty strong case for hydronic or steam heat- with properly insulated pipes of course.

Duct systems also have a nasty habit of pressurizing and depressurizing different parts of the house. This increases air infiltration/exfiltration and if the wrong part of the house is depressurized, it can make a chimney backdraft. Advantage: Hydronics and steam.

Plus, ducts take up a lot of space that pipes don't.

Go here for a comparison that is not as unscientific as it looks at first- scorched-air vs. Steam in similar houses:

http://forums.invision.net/Thread.cfm?CFApp=2&Thread_ID=25079&mc=7

hr

Times they are a changing, Jeffery

Since I left the mountains of Utah,10 years ago, all the savy radiant contractors are now offering HVAC. Yes, it's true the rich and famous are demanding AC and humidification, and HEPA for allergies! Even at the 10,000 foot elevation.

I suspect you will see this in your area soon, if not already.

I agree with Steam regarding duct loss, etc. Although it is only a loss if it is outside the heated envelope. Yeah it does take more motor hp to move air around. At some point, in a large home, a central HVAC system will make more sense than a bunch of humidifiers, and HVR's spread around.

I am a hydronic only contractor, also. But I can see where the market is going Give 'em what they want, or be happy with a smaller piece of the pie. Becaue your competitors will cater to their wants, needs, and DESIRES.

The word is out, AC works in the mountains too! Once the realtors latch on to that concept, it's all over

Team with an HVAC contractor, or two. That's how I handle it and they have sent 4 radiant jobs my way this year, their FA customers!

Something to think about.

hot rod

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Steamhead

But who said

A/C had to be ducted?

hr

Right you are

mini splits are a radiant home's best friend!

hot rod

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Simply Rad_2

Selling out

Yes HR you are right, the realtors are changing everything and AC is yet another change. I still love opening the sliding glass door and enjoy the cool air. Maybe its I am a hydronic installer also and I am terrified of duct work. Actually, I took a class in Boston on chilled water cooling and since I have been slowly reading the text book. I would be more opted to install this type of system, and just subout alittle duct work. My only experience in cooling is with Geothermal using chilled water and fan coil units.
Yea at this point it is hard to decide where to go with the business. My heart is in the high efficiency and comfort systems, but most people do not care. Radiantville is a boom town and people are looking for the cheapest solution. Why should they care because they are going to see the home in 2 years anyway and build another spec home. As long as it last 2 years who cares right!
I may not be the busiest person in town but as you just saw with the Vitodens pics I feel I am offering the most in radiant heating. I feel great about what I am installing and I simply cannot take a step back and install cheap radiant. I would encourage forced air over cheap radiant. Besides if I were that busy I would not have the time to talk with my friends here on THE WALL.
HR thanks for all your input lately
Jeffrey

Steamhead

Any savvy home buyer

is going to look at the utility bills. So if the people you're working for don't expect to be in the house for very long you can still make a strong case for high system efficiency. As energy costs rise- and they will rise- people will look for low operating costs. This could make or break a sale, or determine if the seller gets the asking price or not.

Advantage: Hydronics and Steam!