build new house ....radiant heat?

realolman

I live in the mountains of SW Pennsylvania.     I am beginning the process of building a new house.  I am looking at models of stick built houses from a large builder who has specific models completely designed and priced out... which I like.  He says that changes can be made to specific things, but I am sure that it would slow things down , and perhaps not be as cost efficient as what he already has included. Not necessarily because it's any more expensive, but because they know exactly what they're doing with what they have priced.



The houses come with air to air heat pumps with electric backup.  They are of 2 X 6 construction with insulated concrete form foundations....  this makes an  R30 basement... R 38 ceiling  and R -19 sidewalls.



We now live with oil hot water baseboard and we like it fine.  We mentioned that we would like radiant hot water heat and the guy seemed receptive, but also indicated that it would be a perhaps expensive change, and also mentioned that it takes a long time for the heat to catch up with a sudden weather change etc.... I'm sure they'd rather do what they already have priced.



I think that radiant is probably not as good when the house is carpeted, and I like carpet... but I also think radiant would be good..  I also would like geothermal ( I think ) but it's not cheap....



I would be interested in everyone's  thoughts and opinions on the whole thing... price differences between radiant, and HW baseboard, and hot air.... carpeted rooms  anything at all.





thanks

Mark Eatherton

Now's the time to consider...

You like nice thick carpet on the floors eh... Well, scratch low temp radiant floors off of your list of possible options. Nothing wrong with that. The two just don't work well together.



Consider radiant ceilings. You will need to do the ceilings yourself, because the contractor has never even heard of it. This will deliver a higher degree of comfort than baseboard for sure. Bottom line, anything that affects the MRT within the living space is a GOOD thing. Radiant ceilings, radiant walls, radiant counter tops (warm granite to place your elbows on first thing in the morning :-))



As for cost, if forced air cost $X.00 per square foot, hot water base board may be double that, and radiant floors will probably be three times that, and if you decide to go geothermal, that cost will double at a minimum. The higher the efficiency and comfort factor, the higher the installed costs.



I would reserve radiant floors for the bathrooms. That is where it REALLY makes the most sense. That is where you will most likely be wet and naked and in need of a high MRT (Mean Radiant Temperature).



Contrary to popular belief, you DON'T have to be in direct contact with the heat source (radiant floors) in order to realize radiant comfort.



Another advantage of going radiant ceilings is that you will also be able to base load the cooling requirements of the home with the radiant ceiling.



This will result in a significant decrease in the required size of the air handling components for the AC system.



For radiant ceiling materials, I used Roth Panel in my mountain home, and it works FANTASTIC. The floor actually get fairly warm when the ceilings are running full out. I also incorporated radiant walls and radiant windows. It is a study in radiant comfort :-)



For point of use controls, I'd recommend going with the non electric thermostatic controls (Danfoss, Honeywell, Oventrop and others). You can change the water temperatures at the point of generation (within reason), and the TRV's will flow water proportional to the load, and provide the highest degree of comfort with the least parasitic cost of operation, when used with a variable speed, constant head circulator (Wilo, Grundfos and Taco).



As for the heat source, there are now a couple of air to water heat pumps to make them compatible with your hydronic system. You could have a hybrid. If your local water control agency allows it. You could do a "pump and dump" from your well for the water source heat pump to handle peak load conditions when the air source heat pump starts flailing at low ambient temperatures. Or set an oil boiler or propane or whatever your budget can withstand.



As for the sales mans comments about slow recovery, yeah, if you turn the temperatures REAL low, it will take a while for it to recover. Many times, when the salesman doesn't understand everything they need to know about something, they have a tendency to try and talk you out of it by using price as a talking point. Did they even ask you how comfortable you can afford to be?



I know some attorneys who can put a price on discomfort, but true, high efficiency comfort is PRICELESS.



ME

TonyS

my opinion

Hi Realolman, I built my home very similar to what your looking at 2x6 walls, good windows, maybe to many of them but still my heat loss is 36000 design day.

The downstairs is radiant slab on grade with tile and the second floor is underfloor radiant with aluminum transfer plates with carpet. originally this was heated with a low mass oil boiler w/indirect and as of the last 2 years with a geothermal water to water.

As far as the geothermal goes, I have a water to water unit capable of producing 120 degree water, I have the buffer tank set up on a tekmar reset control and most of the winter I get by with 100 to 105 degree water. This keeps the COP on the geo up in the 5 to 6. But when it starts to get really cold, 15 degrees, the carpet on the second floor inhibits the heat tranfer and It needs higher water temps. We have already decided when we replace the carpet we will use another type of floor covering and use throw rugs( they are easier to clean anyway) My GEO system is a pump and dump, my water is good except a little acid( I use a cupronickel exchanger) and I have a creek next to the house makes for a clean exit. The Geo unit was about the same price as a good boiler.

My heating bill in the winter is about 75-100 dollars.

The radiant heat works well, the colder it gets the more comfortable it becomes. But you do get into these seasons like now where it is cool at night and warm during the day and the lag and lead of the system is out. I corrected that problem last year when I removed the central air system and all that crummy duct in the attic and replaced it with heat pump mini splits, Samsung inverters. They work perfectly taking off the chill on cool nights and they are so efficient for air conditioning I never used the Geo for chilled water( chilled water is a pain). I

This year I am adding a masonry chimney on the house for a wood stove. I didnt have a chimney when I built deciding to go with wall vent equipment but I have learned living a half mile off the road back in the woods that a wood stove , requiring nothing other than wood can be a life saver.

If I would not have had the water for a pump and dump, I would not have gone GEO.

The fields are expensive and the COPs lower. I would have opted for solar panels and another fuel.

I do have 2 solar panels for my domestic and plan on adding more for heat. If you are also planning solar, then using slab in floor radiant can be used as a heat sink for heat storage.

Good luck Tony

hot_rod

radiant in the

bath and kitchen floors if they are tile or hard surfaces. For small bathrooms consider the electric mats. That allows you to warm the bath floors as needed without firing the boiler for a tiny load.



With a house on wood frame floors consider panel radiators. Each radiator gets a TRV for room by room control.



You get the quick response. like HW baseboard, and some radiant.



Check out the Jaga radiators with the small DBE fan assembly, 110F supply temperature.



Remember the solar DHW system, I think PA has some good state rebates on top of the Federal 30%. It goes in easier if it is in the plan from day one.



hr

realolman

would I be a neanderthal if I just went with HW baseboard?

thanks for all your responses... I knew I would get good stuff here.   



I can't say it's made any decisions easier... well,  I guess one... if I want carpet the radiant floor ain't gonna get it.



I am not understanding this statement...





Another advantage of going radiant ceilings is that you will also be

able to base load the cooling requirements of the home with the radiant

ceiling.



If I was to just go with baseboard,  would it be the end of the world?

kcopp

No way....

If you went w/ baseboard sized to run at design say 0 deg. F. and w/ a max water temp of 150F you would be way ahead of the game if you went w/ a mod/con or a control package that takes into accnt for weather responsiveness.... kpc

hot_rod

what it comes down to

is cost and the "look" you are comfortable with. All types will heat the space if designed properly.



With baseboard at low operating temperature you may end up with wall to wall baseboard. this could make furniture placement a challenge?



The beauty of hydronics is you can mix and match all sorts of emitters, and have unlimited control potential.



I ended up with fin tube, radiant floors, radiant ceilings, some custom towel bars and a heated concrete counter top and concrete radiator.



hr



hr

NRT_Rob

not the end of the world

but radiant ceiling can be done very cheaply... such as the same cost as a lower temp baseboard system. and, it's a lot better for any flat ceiling areas. Roth is great but it's pretty pricey.



see attached pic for a low cost ceiling option. I think any case where baseboard is used instead of this is a sadly missed opportunity. ceiling is more comfortable, lower temperature, and if it is more expensive it's not by much. It can be much, much more easily sized to run at geothermal and heat pump temps, so for maybe something like 30% more than baseboard sized for 140, you could have ceiling sized for 110 and be ready to add heat pumps in the future.

CMadatMe

What About Radiant Panel Baseboard?

Have you looked at the possibility of use radiant panel baseboard. Could be cost effective as it would replace the baseboard molding the finish carpenters would have to paint, install and then touch up. Looks just like a piece of molding. You could then get the benifits of radiant heat. Also works well with radiant as the guys have said in the kitchen and bathrooms. Could do the bedrooms with panel radiators also to keep the cost of the material down. Alot of options with hot water just have to look at all of them.

Check out www.hydronicalternatives.com for more information on panel board.

NRT_Rob

"Radiant baseboard"

That stuff bugs me. Technically it uses "radiant" but it's nothing like panel radiators or radiant floor/wall/ceiling which all have low temp operation possibilities.



You can do better with regular baseboard at lower temps than with "radiant" baseboard. the "radiant" stuff has less than half the output at any water temp.



the only nice thing I can think of with that stuff is that is blends in pretty well.



what makes me mad is how they use the term "radiant" and call it "low temperature" heating. it's radiant, yes... but it's definitely not low temp.

CC.Rob

how about...

Panel radiators, piped home-run with TRVs or stats.



Simple, easy to (over)size for lower water temps, easy to pipe, comfortable, etc.