*
I have been studying the concept of radiant heat and have come to this conclusion. If one does not need air conditioning, or has some sort of health issue with forced air then radiant seems like the answer. If one has the dollars to budget for radiant and forced air conditioning, that another possibility. But for me it seems that the best value in todays technology is forced heat and air, with purification and humidity systems attached. I could be off here, so convince me. I want to know the dollars, value and common sense please.
Discussion Forum
Discussion Forum
Up Next
Video Shorts
Featured Story
Fine Homebuilding's editorial director has some fun news to share.
Highlights
"I have learned so much thanks to the searchable articles on the FHB website. I can confidently say that I expect to be a life-long subscriber." - M.K.
Replies
*
Greg
I have been toying with the idea of installing a combined Forced air/radiant system. Basically the basement and lower floor radiant bringing the hot water to an exchanger on the second floor for forced air, allowing for A/C and fresh air exchange.
The cost may not be as economical as a high efficiency FAG unit but there are some advantages, perhaps I'm wrong but here's the logic:
1. Water or Glycol solution can be heated using a wide variety of fuel sources- some yet to be seen on the market-fuel cells for example.
2. There is an option to harness solar power to reduce fuel costs. Present fuel prices are just nuts- our area just hit with a 35% increase in natural gas and 17% electrical
3. One of the most if not the most comfortable building heats
4. no floor registers, dust circulation reduced
5. Lots of tubing but this is easier to hide than large bulky ducts.
just some thoughts, maybe I'm walking a plank
*Brent, I was all into the radiant until the air conditioning issue came up, and it is reflected in the radiant dealers scrambling to find a radiant cooling system. But who wants to be the first user of that system. Not me. I guess if I feel that I have the added money in construction I will also install a radiant floor in conjunction with a forced cooling system. GW
*Greg, My first response is why do we/they need AC, but I realize that is my environmental side speaking.But why shouldn't it? There are alternatives to AC for cooling that work quite well and do not require the consumption of all that power. But I live in a dry climate and do not have to contend with humidity, which if I remember correctly from my time in humid locations is a primary advantage of AC.But back to yiou original question. I have always meant to ask my radiant sub, why not circulate the water during the summer through an addiotional loop that uses the ground to cool the water thus cooling the slab. You could in theory achieve maybe 60deg in your slab which would make a big difference in interior conditions. Granted it would not reduce humidity, but probably make it more bearable.walk gooddavid
*b WBA At Your ServiceDavid, That 60 degree water will cause serious condensation even in your 'dry' climate. Dan Holohan covers this in a chapter in his radiant heat guidebook.
*It's not kind on the budget up front, but consider RFH coupled with a hi-velocity AC set-up like Unico, Spacepak, or Hi-V.Economically warm floors in the winter, no large ductwork/register holes in your framing/walls/ceilings year 'round, and quieter and more efficient dehumidification and cooling from the AC in the summertime.Costs more up front, but depreciate it over 30 years of superior comfort.
*We are installing radiant heat in our two story home.My design will circulate warm water in the winter and during warmer months we will redirect the geothermal ground water through a forced air heat exchanger and blow it out a centrally located vent located high in the cathedral ceiling.We're thinking that it may be possible to siphon a small portion of the cooling medium through our radiant loop in the floor to assist our cooling needs;just beneath the point of condensing.That's the plan!!
*Mongo, Which system do you like the most? Have you used any of them or seen one in operation? GW
*Greg, we have exactly the setup Mongo speaks of (Unico) and it works exactly as he describes. I wouldn't exchange it for a traditional forced air system for anything. I've had elec baseboard, radiators, and forced air in other abodes, and this is the first totally comfortable system. You really don't notice it's there.Don, if your geothermal is like ours, it should be able to produce chilled water just as easily as hot water. Ours creates 40 degree water that we circulate through a Unico system. As for circulating it in the floor, I'm betting that'll not work. I checked into that and was told I'd never be able to control the temps to be able to avoid condensation. You'd have to use water at a temp so close to the slab temp that the delta would not promote heat transfer. Don't risk ruining your permanent floors. Good luck.
*"Which system do you like the most?"Unico-The best hardware in terms of blower units, etc. Nicely detailed, nice tolerances. Spacepak- Has better connections for the ductwork. Easier, faster to assemble, tighter, less likely to fail connections.Hi-V- Probably less sophisticated in terms of design niceties. Kind of a no-frills system. It works, but doesn't have the bells and whistles of the others (meaning fewer snap-together parts, more screwing, it's more laborious to assemble), and the price reflects that. The literature is very basic (not "spartan" basic...more like "hand-holding" basic), which can be good if you're not familiar with these installs. Unico is updating their product, especially the duct fittings. They claim Spacepak doesn't exist, but they sure seem to follow some of Spacepak's more innovative duct ideas.My choice? If hiring it out, I'd go all Unico, with the exception of their proprietary trunk duct, which is fiberglass lined. GARBAGE! It'll be shedding fibers into your living space for years to come. Use metal ductwork for the main trunk line and MASTIC all seams and screws. Seal that puppy tightly.The best of both worlds? Unico boxes and Spacepak ducts. As Unico improves this is less of a concern...it's also more for ease of assembly, which isn't terribly difficult to begin with.For a DIYer? Check out the Hi-V literature. The price is right, and the literature is geared more towards a step-by-step approach. Though the assembly is more difficult.In my house? Unico. The key to a successful install is a balanced system and properly installed ductwork. Use the sound attenuating tube where specified and no sharp bends.
*We call it FANG around here.
*Now that's information! Thanks.
*David, I hope to build this house in Boise. Doesn't it get hot in Montana? I would want air conditioning for myself and the resale value. Is it also possible to get a built in humidification system without going into forced air? My wife says it has to happen. Am I stretching the technological envelope? GW
*Greg, Nice city Boise. I heard some projections that in the next 50 years it will eclipse the LA area for physical and population size. The projection is because the Snake River plain offers flat building and "unlimited water". Lots to do around there as well. All seasons. From whitewater to hiking, skiing, good hunting as well. Hope you enjoy it. I lived in Moscow idaho for awhile in the 80's. Even considered the Boise area myself for awhile. Anyway, Boise climate can be hot and dry for the summers. Winters are cold and dry as well but not as bad as other places inthe northern rockies. Check out http://www.wunderground.com/US/ID/Boise.html This is a great weather site. Also has a bout 10 years of archived weather.Where I live in Montana is similar to Boise, but a bit colder year round. Still we can hit the 90's for a stretch in July and August. But the great thing about living in the rockies is at night it cools off. We often see overnight lows in the 40's even 30's then back into the 80-90's during the day.My thoughts on AC for this area (including Boise) is it really is not necessary. Our house we remodeled, insulated well with good windows. WE get excellent solar exposure which in the summer can easily overheat the house. We simply close the windows and shades/drapes in the morning when we are up and that keeps the house comfortably @ low 70's even with the outside temps pushing 100. In the evening we open the windows and leave them open over night. My wife and daughter usually require a blanket to sleep. We have excellent air flow from bottom to top which creates a natural convection. Sometimes during really hot dry spells, we augment that with a small fan which circulates the air during the day.There are alternatives to AC. I am not up on the Boise market, do not know if AC is even a selling point there. It certainly is not here, though a few homes are built with them every year.As far as hummidification systems, I do not know. I suppose it is probable. We use a portable hummidifyer in the winter. The dryness really bothers my wife then. Plants in the house help, but she is a Minnesota gal.My earlier post about a geo-thermal loop. I am still intreged by the idea. I know there is a potential for condensation, but I was thinking more along the lines of the same effect as using a thermal mass bermed or underground that keeps the temperature fairly constant. I built a house in Idaho which had alot of concrete mass that was bermed to the roof eaves. That house stayed cold (seemingly) in the summer and if there was any condensation it was not noticable. It probably was even appreciated.good luck on your move. if you want just e-mail me directwalk gooddavid
*Mongo. Thanks for comparison of the three main brands. I have been considering each and the info is very valuable to me. I hope that I am not hijacking the thread...but, what do you run between the phlenum and the sound etenuated ends? Do you just run 2" smoke pipe?
*Walt, From the outlet backwards to the trunk line, use the Unico sound attenuating duct. Unico's are 12' long. If the duct run is longer that 12', make up the difference from the end of the attenuator tubing back to the trunk line with Unico "standard" supply ducting. It comes in either 25 or 100 foot rolls.Glad to have been able to help. I should be meeting with Unico this or next week. If there's any new info from them, I'll pass it along.
*
I have been studying the concept of radiant heat and have come to this conclusion. If one does not need air conditioning, or has some sort of health issue with forced air then radiant seems like the answer. If one has the dollars to budget for radiant and forced air conditioning, that another possibility. But for me it seems that the best value in todays technology is forced heat and air, with purification and humidity systems attached. I could be off here, so convince me. I want to know the dollars, value and common sense please.