Hey Guys , I’ve got two new houses coming up in the marshfield area near the cape in Mass. and both house want AC so since we’ll have the duct work i’m thinking about going with hydro air system Now I hate forced hot air by furnace ,way to dry and th humidifiers don’t work in my opinion . Does anyone have any feedback about the hydroair ? Is it still dry heat even know its heated by hot water coils ! I’ve got to be totally convinced before I get won over or use it so give me your pro’s and cons ! Sounds like a pretty good system Is it? Again any input would be much appreciated!!!
Thanks in advance Magnus
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i'll bump ya.......
Every once in a while, something goes right!
I'll bump ya ? meaning what
That means your post has been here a while (11pm 19 Sept) and no one has responded. By then it begins to fall out of sight........I "bumped" you back in to view.
See what happened?
Plus I'm interested in the topic myself.
EricEvery once in a while, something goes right!
hey thanx firebird ,Its been a while since i've been back to breaktime thanx>
Every time I've had a project that it seemed appropriate for, the client decided it was too expensive. I've had high hopes for it, but we've never been able to overcome cost.
Thanx for your response cloud hidden , We're having AC so we need the ducts and if we go with Forced hot water we need the boiler and it would eliminate basebds. or we could go with basebds. downstairs and hydro up ! And we could go with radiant downstairs , now that would raise the cost! But regardless of cost do you know of any feed back on the system? thanx again
Magnus
Hydro air has been installed in all the homes I have done in the last three years. The Builder I work with uses it because of ease of installation and he says it isn't as dry.I did a home for a building inspector last year and he installed it. I will ask him for an honest assessment. You wouldn't think it would be a problem getting a supply and return in a 5000 square foot home, but when the architect doesn't pencil it in, the fun begins.
greg in connecticut
Dryness won't be any different than with hot air. Humidity is determined only by how much moisture is released into the air, how much diffuses out through the building envelope, and how many air changes there are with the outside. If those things are equal, than any source of heat is equally as humid or dry as another.
Wayne is right. All heat sources are doing (except for humans themselves, leaving the hot water faucet running, and burning an open campfire in the living room).
RFH, FA, rads, heat pump - All heat air, directly or indirectly, without adding water. Unless there is a humidifier in the loop.
What does make for "less dry heating" is a tighter house. Because the humidity generating while living your life isn't lost to the environment so quickly.
People are left with the impression that new systems (RFH, hydro air heating, heat pump) aren't so drying as old systems (FA, rads, etc) But really, it is the old leaky houses that made for dry air.David Thomas Overlooking Cook Inlet in Kenai, Alaska
I cant say I agree , In the case of forced hot air , air is heated with a flame , a furnace , which basically sucks the humidity right out of it and as the air is constantly circulated with cold air returns it tends to suck the moisture right out of the house ! This is why they put a humidifier on forced hot air systems which don't work very well. I used to live in a house that had FHA and every winter I would get nose bleeds and dry patches on my face from the lack of humidity> Hydro air which is heated by hot water coils ,as I under stand heats air at a lower temperature too .I agree on all other heats but like I said its the flame that drys the air>
David is right. The dry air is caused by a lack of sufficient combustion air being allowed directly from outside to the furnace room. It has to come from somewhere, usually from every door and window frame. That outside air is dry. If you have a combustion air vent next to the furnace, you eliminate a lot of the drafts and start to control the humidity.
When we install a new furnace, the chimney often is reduced from 7" to 5", and we install a combustion air vent. Comments about increased humidity in the house are not uncommon.
The supply temperature from a hydro coil can often be higher than the supply temperature of a new furnace.
"In the case of forced hot air , air is heated with a flame "
No it is heated with a heat exchanger. Just like it is heated with hydro air.
What is on the other side of the imprevious heat exchanger does not affect the humidit level.
Yes Bill but my point was not that ! Furnace heats air to 190 degrees not that the air was actually passed over a flame Like you said both are heated by heat exchangers but alot diffent temps which makes difference in humidity of air
"Furnace heats air to 190 degrees not that the air was actually passed over a flame Like you said both are heated by heat exchangers but alot diffent temps which makes difference in humidity of air"
Heating of the air does not reduce the moisture level in the air. What happens is that the hot air can hold higher moisture level so that the RELATIVE humidity level is less.
And it really does not matter how hot that the little air that passes over the heat exchanger gets.
Take 2 house houses. One with hydro air and one with gas FWA. Let them start at the same temp and humity level.
Then warm them both up to 70 degrees. The relative humidity level in the two will be exactly the same.
Bill's right, of course. But to further clarify. Air going to 190F will be of lower RH than air going to, say, 130F. But for the same house, same tightness, half as much hotter air will be blown around to meet the same BTU demand.
Moisture in the house = moisture in - moisture out.
Moisture in = breathing, showers, sweating, humidifiers.
Moisture out = leaks in the building envelope.
Dry house? Get hot and sweaty more often. Or plug the leaks.
Choice of heating system doesn't matter. Unless you spec a humidifier in the heating system, duh.David Thomas Overlooking Cook Inlet in Kenai, Alaska
As Bill pointed out, moisture is not "sucked out" by the flame. The flame is on one side of a piece of metal. The house air in on the other side. Water vapor does not diffuse through that metal heat exchanger.
Indoor RH is a function of how much mositure is released by inhabitants activites and how much is lost through air leakage. As Rich noted, one form of leakage can be combustion drawn from inside the house. Drawing combustion air from outside is better. With any kind of heating system.
Older houses often have FHA. Older houses are leaky.
Hydro/air systems are newer. Newer houses are less leaky.
If two houses both need the same BTU/hr, it doesn't matter whether the BTU are moved in a smaller amount of hot air or a larger amount of warm air. What matters is now many BTUs because that is a measure of the air leakage.
If you had NO leakage, indoor RH would go to 100%.
If you have total leakage, during a 0F snowstorm outside, inside air would be 26% RH and your hands, lips and feet would crack and bleed.David Thomas Overlooking Cook Inlet in Kenai, Alaska
Actually it goes a lot lower than 26%.
Ask my wife.
That seemed high to me, but I read it off a pyschrometric chart.
Oops! Found the error. I looked at the 0C line instead of 0F.
So, again, corrected:
100% RH at 32Fwould go to 26% RH at 72F (I used 72F because of the very dry air)
100% RH at 0F would go to about 8% RH. Which would make your lips crack and fall off.David Thomas Overlooking Cook Inlet in Kenai, Alaska
I had hydro-air installed in my house at new construction. I cant say it is not as dry as a hot air system since I have nothing to compare it to.
I will tell you the first year was really noticeably dry. I had a humidifier that puts up to 20 gallons per day installed on the return air duct. This allows me to control the humidity level.
Three years ago you posted on FHB that two clients wanted hydro air HVAC systems. Did you end up installing them? If so, I'd appreciate any feedback from you as the builder and anything the owners might have said after the fact. I'm building in the Berkshires and going nuts trying to decide on an HVAC system...
Thanks,
Sherri