Forced or Radiant-new construction-home owner

Ron Conrad

I will soon be building a new home for my family. Trying to decide on the cost and benfit factor of Radiant over Forced air.
*2200 sq/ft main floor with identical daylight basement(western exposure).
*Flooring-only tile in bath and entry way and wood floors throughout the rest of the home.
*Energy options propane or electric.

Question 1-Is having the water in the Radiant Floor Heat system the same as my drinking water safe(assuming contractor installs a regular cycling system)?
Question 2-What is the best boiler for the money?
Question 3-Do I spend the extra $11,000 on the Radiant system($29,000 compared with $18,000)or is it just a comfort thing?
If I saved the high end estimate of 40% on heating that is a long time to make up the 11 grand.

I am trying to determine if the benefits outweigh the costs (since we need air conditioning hence duct work in this area my cost is $29,000 total HVAC using radiant compared to $18,000 for a nice forced system.
My HVAC contractor bid the job using:
2 Polaris APG10501003 Water Heaters (100,000 BTU 50 gallon)for the radiant.
or
1 Trane TDX120C960F Furnace(120,000 BTU/90%) for the forced air system.
I am looking for any thoughts.

Climate Creator

How do you put a pice on COMFORT?

Don't worry about how long it will take to pay back, worry about how you will feel during that time. I have forced air in my home, I HATE IT!! I put radiant in other peoples homes and always say I can't wait until I do mine, but that day has not come yet. At least you GET a payback from radiant, what do you get from the heated can? Besides an upfront savings? I am never comfortable in my home unless the unit is RUNNING which makes us keep turning the tstat UP all the time running near 72 sometimes, where as you could run radiant floor at 62 constantly and be VERY comfortable, put radiant in, you'll sleep better, guaranteed!!

CC

rod robbins

I think there is no qustion that radiant heat will be the most comfortable heat to use.I would not build a house to live in with any other heat.I would not mix my domestic with the radiant I dont care how safe anyone claims.
Rod

don_23

From

where I set,11,000 more not looking bad for a system that
has so many benefits.

However if you'll going to go infloor why not go with something that you can modulate the btus?
Here the problem when you go force air,you have to design
the heat around the ac no buts about it.So when doing so
you know in order for ac to work correctly,it needs to fall
because the law says so.Now think in turns on the heatside.
Hotair rises.So placement of the vents need to be on the floor on outside walls.See where I'm going here?

If 11.000 allow for seperation of the heating system
and cooling system,where one can enjoy comfort all year and
not having to sacifice one for the other,then it looks like
a great investment to me.Not to mention how creative one can
get to drop those btus off where and when needed.

Boilerpro_3

Payback

Don't forget that your A/C will also be more efficient if you install radiant plus separate A/C system. Your ductwork can be designed for maximum cooling efficiency intead of being compromised by have to desing it to also have hot air running through it too.

Boilerpro

Constantin

I'm just a Homeowner

but I had to make similar decisions when it came to renovation of our Mansard. In the end, I decided to go with Radiant heat and central AC. Here is why:

1) Use technologies where they are best. Radiant is really good at heating rooms comfortably, AC is good at removing heat from them. A forced-air system that has to do both is always a compromise: Air outlet register placement is usually optimized for whatever mode predominates (heating or cooling). By going with an AC-only system, you give the contractor the opportunity to optimize the systems cooling capacity and hence your comfort.

2) Allegedly, Radiant heat requires lower setpoints on the boiler/thermostat for the same comfort. According to the DoE, every degree lower on your thermostat results in a 3% energy savings, IIRC.

3) Heat Gain and Losses are typically not alike. Depending on house construction, insulation, exposure, etc. combined duct system may need to be much larger than AC-only systems. By going with an AC-only system, you may gain some space inside the house (smaller ductwork).

4) Radiant feels great under feet.

Etc.

As for what system to use to heat the house, I'm not sure I'm a great fan of systems where potable water makes its way through the house first (even though one vendor states it may help cool the house, etc.). Regardless of how innocuous PEX is, I prefer separate loops for passive safety. That gives you the freedom to add glycol to the mix later on if you want to be extra-safe in case of a extended power failure during a cold winter. My mum went without power for a week in Maine during that freak ice storm a few years back. It's nice to know that the system will not self-destruct.

I have read good and bad things about the Polaris heater series. I prefer sealed combustion appliances and for the money I'd go with a Munchkin and a indirect water tank on the primary loop. A bit more money but allegedly a bit more reliable as well. Heat Transfer Products' Munchkins can run on propane.

You state that only propane and electricity are available. Are you sure that no-one in your county is willing to deliver oil to you? Both electricity and propane are very expensive fuels. If oil is an option, take a another look. At least in Boston, MA, the per BTU price of oil was about 40% below that of natural gas (never mind propane!) this winter.

I calculated that even if we held gas prices constant, the average price of heating oil would have to approach $2/gallon before oil would be more expensive than gas in Boston. Furthermore, over 70% of the gas cost is fixed at NStar just for transmission/distribution (about $0.90/therm), so even if the price of gas went to zero, natural gas would still be more expensive than oil delivered (currently, local year-long supply contracts are at $1.15/gal or $0.82/therm).

Lastly, I would be extremely surprised if gas prices (now at $1.37/therm for residential heating) would not mount in line with oil prices. Typically, they are broadly correlated. There is a good reason for folks to cling to oil in the NE of the US.

Robert O'Connor_3

Polaris issues

Check other threads on this site. Some have had multiple ignitor problems with the unit. They're not cheap, and as said, might as well get a wall hung modulating boiler with a single indirect tank for doestic HW.

Bob Gagnon plumbing and heating

a forced hot air guy

came to a house that i'm installing radiant in. he was giving a price on air conditioning, and HE agreed "radiant is the way to go with seperate air conditioning" and they don't install radiant. bob

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S Ebels

We do both

Two of the new homes we are doing this summer are going to be set up as follows.

They both have finished basements which the owners want to use as living space. This, in my experience virtually dictates that we use a radiant floor. Without fail, homeowners who construct a finished basement and try to make it comfortable with a forced air system, are sorely disappointed. You are defying the laws of physics. You always lose when you do that. Always. Running the fan on your furnace or airhandler constantly 24/7/365 is the only way to achieve minimal levels of comfort on a lower level. Notice I said minimal. A radiant floor in the basement is the only way I will offer a customer a garuantee of comfort.

Many customers want cooling also and as several have mentioned here, asking the same system to deliver both heating and cooling, compromises both. Better to have them seperate.

On the subject of "combined" heating and domestic water systems, I refuse to expose my customers to this. If they want it, they become a customer of someone else. I wouldn't sleep well knowing I had opened up the possibility of making someone ill or worse.

All that being said, here's what we have done a lot of where radiant is not desired in the whole house and where cooling is a requirement.

Basement: radiant, zoned as the customer wishes. Usually with panel rads or BB to provide quick or extra btu's when and where they are needed.

Main level: Radiant in areas where it's wanted, such as bathrooms, entry, living rooms etc. Then we will install an airhandler that incorporates heat recovery ventilation into the system. This would be like a clean air furnace from Nutech (www.lifebreath.com) to provide air movement for the forced air portions of the home. The duct system is set up mainly to provide circulation to the upper level as that is where the cooling is needed. You can use the laws of physics to your advantage in a cooling scenario as far as the basement goes. It will happen naturally if given the opportunity. Your boiler provides hot water for the heating part of the air handling system. Forced air zoning can be done also to provide you with maximum economy and comfort levels.

Also included in these homes is an indirect fired water heater, driven by whatever boiler is chosen.

That is a very brief and undetailed picture but gives you some idea of what you can do if you utilize hot water as the primary heat source. The system described here, if installed and designed correctly wil give you,

A. Economy of operation.

B. Fresh air ventilation with heat recovery of exhausted air.

C. Air cleaning/filtering

D. Humidification

D. Dehumidification

E. Outstanding comfort levels, both heat and cooling

F. Good reliability and service life with the right components.

G. A home that is livable and comfortable in all areas.

H. A "healthy" place in which to live. In other words a home that won't increase the probability of you and your family getting sick.

I. Copius amounts of hot water, generated as inexpensively as possible.

jackchips_2

I share

Climate Creators misfortune of having forced "Warm" air. Not scorched, not hot--warm :-)).

Because of living on a slab on grade without an attic and the steel pipe radiant letting go I was "forced", in the middle of winter, to put in the existing system. Oh do I miss those warm floors.

The existing system wasn't any where near the problem it is as I get older. The constant swings in temperature make the house very uncomfortable, especially when it is very cold out.

The only comment about the cost is, if this is your long term home, it will be more than worth it and that is the way to go.

Ron Conrad

Thank you for all the responses.

Dad

I wish I had the option in my new condo for radiant - floor-heat

This new condo has the worst heating system made. It had to be designed for southern states. The gas furnace is located above the garage. It is slab construction with no insulation under the concrete.

The worst design problem is that the airvents, Cold and hot are in the cathedral ceilings. The one, large return air duct is also in the top of the cathedral ceiling.

With the large increase in natural gas this past year, we have had $400.00 bills. I have experimented with thermometers placing them at floor level, chest height and at the top of the cathedral. 67, 73, 78 respectively. The 78 at the top doesn't help much. The ceiling fans only moderately move the air. Do the right thing, Son, and put in radiant heat.

Uni R

Warm feet option

Dad, there's some encouraging news. Electric carpeting is coming. The Japanese and Chinese manufacturers are ramping up. Use it in the rooms when you are occupying them... Should be great for your type of application.