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Youngster
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Discussion Starter · #1 ·
It is getting to the point where all HO's want radiant only for heating. I can't blame them. Radiant floors IMO is far superior to forced air heat, especially in my climate.

I've always made a case for forced air on the grounds of cost, "because the ducts are going to be there for the A/C anyway". But I can't in good conscience continue to persuade clients to settle for forced air heat. Also, these are high-end homes in high-end neighborhoods, and they realize their compromise as soon as they visit the neighbors.

But, if I start supporting radiant heat on all floors, what should I recommend in terms of cooling? I'd considered high-velocity at one point, but additional research has steered me away from that. Do I just stick with conventional and make them swallow the pill of single purpose ducting?
 

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It has been suggested to me to just include a furnace. What is the big deal about another $1000, and it can be used as another poster suggested, when you have those cold snaps early in September. At that point, you may not want to take the time to heat the house up with the radiant when it will be warm again the next day.
 

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Youngster
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Discussion Starter · #5 ·
Why not heat pump with radiant floor? It would serve as a backup in case of problems with the floor heat, and, I believe, it is more "energy efficient" during the mild temps during the spring and fall.
Not really familiar with the preferred setup there as I'm not an HVAC guy. Could you provide additional info?
 

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You can as Flash said install a heat pump for energy savings.

Or, you can include a hydro coil with the central air. As a second stage of heat. If you have a problem with getting enough radiant in the floors.

Our job is to advise customers what will and won't work. And the pit falls of any system they are interested in.

And then let them determine what they are willing to pay for. After all, it is their house.

If you limit the type of systems you are willing to install. You eventually, limit the amount of work you get.
 

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Chief outhouse engineer
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I'm not a HVAC guy, but I knew the benefits of radiant when I built my house almost 10 years ago. I have a single story ranch with full basement and radiant all over. We installed the AC duct work in the attic and just a single vent in the basement as it needs very little additional cooling in the summer.

I found that the radiant was a little slow reacting to large temp. swings that we experienced. Some days we would hit 50 during the day and drop into the teens or less that evening. By placing a "Hydro loop" or as I referred to it as a radiator in the AC exchanger we solved the slow response of radiant and avoided the need for expensive electric heating coils for a backup.

Our humidity in the summer insured that we were going to have central AC and the heat loop sits dormant on top of the AC coil in the summer. Construction costs ended up roughly the same and I get to enjoy warm floors when it is below zero outside.

If your needing central air, I see no way around the duct work. Once your planning the duct work, its a no brainer to address the one weekness of radiant which can be slow response time.
 

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Thom
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I put radiant in-floor and a ducted A/C-Heat system in my house. The ducted system was for A/C but the heat added little cost.

Radiant can take a while to get up to temp. In the fall and spring you may not want to keep the floors warm yet want a little added heat to the air.
 

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Youngster
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Discussion Starter · #10 ·
Strongly considering going the route of geothermal heat pumps with radiant in the next home. They are installing solar for power, so the idea of heat pumps makes a lot of sense. Adding additional capacity to the solar is cheap after the initial install, and the system could then provide both heating and cooling at very little cost to the HO. In the process of trying to figure out how many heat pumps would be needed. The home will have radiant on both floors as well as garage, walks, and driveway.
 

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Cache;848099 In the process of trying to figure out how many heat pumps would be needed. The home will have radiant on both floors as well as garage said:
Your going to need a lot of wells.

Contact Wirsbo to see how many BTUs you will need. For those wolkas and drive way.

They can and will size the whole job for you.
Don't forget to use floor sensors.
 

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Strongly considering going the route of geothermal heat pumps with radiant in the next home..................... and the system could then provide both heating and cooling at very little cost to the HO.................. The home will have radiant on both floors as well as garage, walks, and driveway.
Will provide low cost heating and cooling after the initial investment of $200K:laughing:

More money than brains.

Buy a sweater and some rock salt
 

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Youngster
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Discussion Starter · #13 ·
Will provide low cost heating and cooling after the initial investment of $200K:laughing:

More money than brains.

Buy a sweater and some rock salt

Actually, the quotes are coming in at a very reasonable cost. I think there are a ton of misconceptions out there regarding solar, geothermal, etc.. Especially as they relate to new construction on a larger lot.
 

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Youngster
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Discussion Starter · #15 · (Edited)
Do those reasonable prices include the driller and grouting.
By wells, are you referring to deep vertical wells of like 200' depth? Those aren't necessary in this area. Lot is 2/3 acre so there isn't any need to go deep. Geothermal around here means that they dig 3' wide trenches and use the slinky method. For this house I'd need about 200lf of trench at 6' depth, which would run about $1,200 with backfill. Soil here doesn't usually require grouting. At the very most, about $300 worth of sand would be brought in. About $2000 for the PE pipe, and $4,000 for the heat pump. Radiant floors are going in with or without the geothermal.

Walks and driveway will be very intermittent. We get a lot of cold days, but they would only be kicking on the heat to the drive for a few hours about once a week Dec-Feb, to melt off a couple inches of snow. They said that they are willing to manually shut off the basement radiant floors during that time, until the snow melts.

Each boiler or HE condensing water heater carries a price similar to that heat pump, so the extra cost is do-able. Also, there is a 30% tax incentive for geothermal.

A sufficient PV solar system will cost them about $15K in the end, after rebates and credits, and will generate about 9,000kWh each year. Financed into the mortgage, that is about $85/month.
 

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Snow melting takes a lot of heat. Even just a couple inches.
A lot more then to heat a house. So it better be a small driveway. Or they'll be without heat in the basement for days. And their ground temp will drop a lot.

You should get a rep from what ever company your getting the geo from. To size it out. And give you the possibility of using it for snow melt.
 

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Youngster
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Discussion Starter · #17 ·
Snow melting takes a lot of heat. Even just a couple inches.
A lot more then to heat a house. So it better be a small driveway. Or they'll be without heat in the basement for days. And their ground temp will drop a lot.

You should get a rep from what ever company your getting the geo from. To size it out. And give you the possibility of using it for snow melt.
Yeah, rule of thumb says at least 100btu per square foot. That's about 3X what the house needs. But all documents say that the 100btu capacity will keep up with 1.5" snowfall per hour. I don't need anywhere close to that. What I am looking for is a system that will simply melt a couple inches of snow sometime after it has fallen, but in about a 3-4 hour timeframe. It doesn't have to keep up with snow that is accumulating at 1.5" per hour.
 

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It takes more heat to melt the snow after it has accumulated. Then to prevent it from accumulating.

To melt 1" of of snow in 3 or 4 hours will take closer 600BTUs per sq ft(figured on a light weight fluffy snow, at 7 pounds per cubic foot). Snow is a good insulator. After it accumulates, it tends to make the heat from a snow melt system go into the ground. Instead of melting the snow.

A wet compacting snow, will weight around 15 pounds per cubic foot. And will take twice as long, or more then twice as much heat in the same time period.

If your going to install a snow melt system. Why not use snow sensors and do it the right way. Prevent accumulation.
 

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How many LEED points to you get for using a HP on your driveway radiant system?

It's just a gross and irresponsible waste of money and resources.
 
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