My husband and I live on Long Island so our winters are tempered by the ocean( we are not on coast though). So not that cold; occasionally for a few days around the teens.( Zone 7)We have an old 2 story colonial we are in contract to sell ; we already have a piece of property bought where we want to build a senior friendly home for our last 20 years or so.Our architect is drawing plans now and we will start construction in October. The house will be one story( about 2000 sq) on top of a walk- in basement( we are on a slope). We are considering Radiant heat floors, but will still have to have duct work for central air. Some are saying this is ridiculous and we should just go with forced air. Before we decide might someone here help with a few questions? 1. What about termites? Some say radiant floor is bad if you get them 2. I like a house warm in the day( about 67) but cool at night( we set down to 55 now in a old radiator heating system) for sleeping. Can we have a separate zone for the master bedroom and have it lower? But then I like a warm to hot bathroom for showering. Should we just plan a separate heating source for quick warming of bath? 3. I read that the Warm Board system heats up quicker. Would this be better? And how is this for the termite issue? 4. How efficient is it for a refrigerator? Or is that in an area of floor with no heat? 5. Last we love wood floors and it will be an open floor plan. Is it true bamboo is best with Radiant? Should it be floating? And can I have a small area rug under couch in living room? What is a source of information that is reliable and not pushing a product? Just the facts?

Good questions!
1. Termites are just plain bad, don't get them. I Don't see them being any worse for above floor radiant than any other wood floor structure...
2. A low mass radiant system will respond fairly quickly to accommodate setback temps. You can also build specific heated zones like master bedroom and master bath to fit your desires. A higher mass system like qypcrete stores heat so will take a longer time to warm or cool after a thermostat change.
3. Yes an above floor/low mass system such as warmboard or RHT will warm and cool quicker and respond faster to thermostat changes. I don't see them being any more of a termite issue than a traditional plywood subfloor would be, as they typically only run a little warmer than the thermostat commanded floor temp(probably not as warm as your roof framing will typically run most of the year).
4. You do not typically place radiant heat under appliances or cabinets, just like you probably don't find your steam radiators in closets The floor needs to be warm to transfer the heat into the room. Heated floor under an appliance or cabinet(like a radiator in a closet) does not heat the house.
5. The denser the wood, the better it typically transfers heat. One possible issue with a floating floor is the mat they are typically put on. This mat is an additional layer of insulation between the heating element and the floor surface that transfers the heat to the room. Best to have the flooring in direct contact with the radiating surface. This will allow the lowest radiating temps to be used(lower water temp, less plumbing loss) to meet the heat loads of the house. The same is true of an area rug, it "blocks" the heat transfer to the room, like putting a sweater on one of your radiators. A detailed heat loss analysis of your design can tell you how much heat you need and how much of an effect a given size area rug will have on heat delivery. Heat transfer is basically(very basically) about surface area, conductivity of the material, time and temp difference. If you block a certain amount of the heating element surface with a rug, you have to run the rest of the surface at a greater temperature to meet the heating demand...

Thank you!

Since I wrote the post I spoke to two families who have radiant heat and they say they have no problem with termites. They also have solid wood floors and have no problem with cupping or these type of issues. Only funny thing they found out was they couldn't put a garbage can on kitchen floor or the garbage would start to cook! I wouldn't have this problem as long as the garbage can is under sink area of cabinets where there is no heat placed.

And yes I saw a video yesterday that showed how the installers cut out and go around things like refrigerators and toilets. I will keep in mind the area rug point as far as figuring out heat loss.

And I am leaning toward a solid 1/4 sawn oak floor as I read this is some of the most stable wood and good for radiant

Now to think about boilers and water heaters etc. But I think that requires me to research more and maybe go to a different thread

In a new house you can design the heat load to be low enough that the radiant floor never gets hot enough to affect the wood. (At your modest ~+15F outside design temperature even in a sub-code minimum house would not present a problem for the wood.)

Comfort is all about average radiant temperature, and in a high-R house with better than code windows the surface temperatures of the windows and walls will be considerably warmer than what you're probably used to, which takes away some (but not all) of the additional comfort of radiant floors. There is often a better bang per buck to be had by spending the radiant floor money on a higher R house, from both an energy use and a comfort level.

You are actually in DOE US climate zone 4A, not 7 (which is what, a plant hardiness zone?) Long Island's wintertime conditions are well suited to getting maximal efficiency out of ductless or ducted modulating air source heat pumps (mini-splits), which can be a fraction of the cost of a full hydronic floor heating system + ducted split heating system. If the heating fuels for the hydronic system are propane or oil (rather than natural gas), a cheap electric boiler keeping the floor at decent temp (say 72-73F) operated by floor thermostat, and mini-splits setting the room temperature at the same or a degree warmer than the floor can be substantially cheaper than heating with propane, comparable or slightly cheaper than heating with oil, and only slightly more than heating with gas, depending on the local fuel prices. The key is to keep the mini-splits and room temp at a temperature no lower than the floor temp. A 73F floor in a 68F room feels pretty good, but is emitting a lot of heat out of the floor. A 73F floor in a 73F room heated by mini-splits feels even better, but the amount of power going into the floor is negligible- the mini-splits are carrying the vast majority of the heat load, using a third or less the amount of power as an electric boiler.

Or you can skip the radiant floor spend it on a high-R house, and heat with mini-splits.

Electricity prices on L.I. are on the high side compared to the national average, but rooftop solar's lifecycle levelized cost can be substantially below LIPA rates, and if net metered it can make heating cost quite a bit less. Solar is getting cheaper every year, and financing it as part of the house at mortgage type interest rates would be cheaper than doing it later. The federal income tax credit subsidy will be dropping back in a few years, but you have time. The NY regulations around compensating residential PV are also changing, but is expected to be pretty good for at least another few years.

With whole-assembly R-performance found the zone 4 row in Table-2 of this document it's pretty easy to hit Net Zero Energy with a PV array that fits on the house:

https://buildingscience.com/sites/default/files/migrate/pdf/BA-1005_High%20R-Value_Walls_Case_Study.pdf

With net metering and a Net Zero house you would have NO energy bills for heating & power, at the cost of only a modest uptick in the mortgage, if you do it right.

Note, those are "whole assmembly R", not center-cavity R values. The suggested R25 wall isn't a 2x8 framed house with R25 batts, since the framing conducts quite a bit more heat per square foot than the batts. eg: A code-minimum 2x6/R20 wall runs about R14-R17 "whole-wall" after thermal bridging depending on actual framing fraction. the siding & sheathing choices, etc, but with 2" of continuous rigid rock wool or rigid EPS, or 1.5" of rigid polyiso between the structural sheathing and siding that jumps to R22-R25, which would be good enough.

That analysis was done in 2008-2009, when PV panels were 15% efficiency instead of 20% and cost 2-4x as much as they do today, and better class heat pumps had an HSPF efficiency of about 10, rather than 12-13 today. You'll definitely want to be better than R20 on the walls, but doesn't necessarily have to be the full R25. If you opt for foam sheathing, it's a lot cheaper (and enormously greener) to use reclaimed roofing polyiso, since the material cost is about 1/4-1/3 that of virgin stock foam, and no new polymer or blowing agents are being used. There are probably a few square miles of 2" & 3" roofing polyiso stacked up in foam reclaimers and salvage warehouses in the northeast within easy trucking distance to your site, eg: https://newyork.craigslist.org/brk/mad/6038332560.html

The shape of the house makes it easier or harder too. The more bump-outs, corners, dormers & roof valleys there is to deal with, the higher the framing fraction, which lowers the thermal performance, and the more exterior surface area there is losing heat per square foot of living space. It doesn't have to be a cube with a gable, but keeping the footprint to no more a than 6 ( an L topology) or 8 (T topology) helps. Fewer corners also makes it easier to air seal to acceptably tight levels too.

Thank you Dana1

Ha ha yes I am a gardener and my plant zone is 7. Sorry about that. We only get in the teens once in a awhile for very brief times.

I am not sure I understand enough about heat pumps as to your point above about not using RH floors. Where I live our town forbids Geothermal as it is bad for our aquifer( we have mostly wells here). They say that system would draw in salt water from nearby bay.Both closed and open loop are banned. Is this what you are talking about?

We are building a one story for main living area, but it will not be a ranch. The architect hasn't even drawn the preliminary plans yet so I can't say exactly what house will look like in terms of nooks and crannies, but I don't think too many.But we will have some vaulted ceilings in master and living room area. We will have a gas fireplace too as now we have a wood fireplace and it loses way to much heat up the flue. And it is too messy ( but God I love it). Again one reason I like the RH floor is that there is less dust circulating. I want this to be an easy case home and I hate to dust!

Windows and insulation are up to my husband who will be the GC. But we are paying cash for the build with no mortgage and we will be doing everything the right way both in terms of quality and energy saving products. I will talk to him about your suggestions.

We bought the property awhile ago because we love the trees. It has over 100 ft oaks and beech trees on the acre piece of land. We won't be be able to have solar panels unless we cut down most of trees which we will not do.

We probably will be using fuel oil as I had a bad experience with propane ( a heater in my garage caught on fire.Luckily I was just going to get car and saw it.)and it is too costly here.I gather we will need a boiler for the RH which now are very energy efficient. And then a water heater too. But I have much research to do about all that.

And thanks about the floors. I spoke to several people who have RH floors and they have no problems with their hardwood floor. So that is decided that we will go with solid oak.

If you don't like dust, install a central vacuum system that exhausts to the outside. That plus HR heating system will practically eliminate any dust in the building after a few months.

+1 on considering more insulation and perhaps PV and skipping the radiant heat.

I gather we will need a boiler for the RH

You can use a heat pump (eg, Chiltrix) and electricity - typically at a better price than fuel oil or propane. Highly unlikely to catch on fire :-).

Can we have a separate zone for the master bedroom and have it lower?

If you want 12F lower, then put some insulation in the interior walls.

We are in the same boat as you. We live in and are building another house with high thermal mass. It take a couple hours to change the temperature in the current house with R19 walls and new house has R30 walls so it will be worse. and the temp is not going to change any better at night for sleeping.

So we are leaving the house temp constant like we do in the current house but have bought what is called a Chilipad for our bed to keep us cool at night. It is the greatest thing. We sleep great now and are never hot. It is a air conditioner for your bed that circulates cold or warm water through a mattress pad. It was expensive but worth it. Good Luck.

Posted By Sailgranny on 31 Mar 2017 09:43 PM
Thank you Dana1

Ha ha yes I am a gardener and my plant zone is 7. Sorry about that. We only get in the teens once in a awhile for very brief times.

I am not sure I understand enough about heat pumps as to your point above about not using RH floors. Where I live our town forbids Geothermal as it is bad for our aquifer( we have mostly wells here). They say that system would draw in salt water from nearby bay.Both closed and open loop are banned. Is this what you are talking about?

We are building a one story for main living area, but it will not be a ranch. The architect hasn't even drawn the preliminary plans yet so I can't say exactly what house will look like in terms of nooks and crannies, but I don't think too many.But we will have some vaulted ceilings in master and living room area. We will have a gas fireplace too as now we have a wood fireplace and it loses way to much heat up the flue. And it is too messy ( but God I love it). Again one reason I like the RH floor is that there is less dust circulating. I want this to be an easy case home and I hate to dust!

Windows and insulation are up to my husband who will be the GC. But we are paying cash for the build with no mortgage and we will be doing everything the right way both in terms of quality and energy saving products. I will talk to him about your suggestions.

We bought the property awhile ago because we love the trees. It has over 100 ft oaks and beech trees on the acre piece of land. We won't be be able to have solar panels unless we cut down most of trees which we will not do.

We probably will be using fuel oil as I had a bad experience with propane ( a heater in my garage caught on fire.Luckily I was just going to get car and saw it.)and it is too costly here.I gather we will need a boiler for the RH which now are very energy efficient. And then a water heater too. But I have much research to do about all that.

And thanks about the floors. I spoke to several people who have RH floors and they have no problems with their hardwood floor. So that is decided that we will go with solid oak.

Not geothermal heat pumps, but modulating air source heat pumps (mini-splits), which in your climate are nearly as efficient as ground source heat pumps at a fraction of the up-front cost. (Spending the difference on roof top solar often makes more economic sense. Ductless mini-split do not recirculate dust, and do not pressurize or depressurize rooms the way ducted systems can. And at IRC 2015 code-maximum air leakage levels (the leakiest house that's still legal to build in NY) a new home simply won't be very dusty in the first place. Ductless systems take air from one side of the cassette or coil and return it to the same room only inches away, and are not dust-distribution systems. The blowers modulate speed with load, and at low speed are on the same sound levels and air volumes of a typical refrigerator's blower (or lower), and they have filters. They are in no way comparable to the typical 3-5x oversized scorched air furnace with duct system. Ducted mini-splits typically serve 2-4 nearby rooms with short duct runs, and they too modulate the air flow with load.

Using reversible hydronic chillers such as the Chilltrix can work for radiant floors, but (unlike ductless or ducted mini-split air source heat pumps) the system requires substantial design to work well, which adds to both risk and expense. Getting local design support & ongoing support for such a system may be difficult, whereas there are dozens of mini-split installers within an hour's drive of most Long Island locations.

A gas fireplace has almost no place in a higher-R highly efficient house, since the heat output is usually too high. If you're going to install one anyway for ambience, pay close attention to the heat load number for the room, and the minimum heat output of the unit, as well as it's air-tightness. "Sauna" isn't usually the ambience people are looking for in a fireplace, but that's often the result when installing them in highly efficient houses.

Getting rid of all combustion appliances and going all-electric isn't as insane as it might seem. Heat pump water heaters do double-duty as dehumidifiers (not that it's ever sticky outside in the summer in your location :-) ), induction ranges & cooktops are safer and about as responsive as a gas/propane solution, and heat pumps do double-duty as heating & cooling appliances. No high-priced micro-monopoly propane service, no tanks of stinking oil that need to be kept indoors to avoid jelling with potential to leak and contaminate the house and site. Yes, you're stuck with the LIPA regulated monopoly, but at current utility pricing and heat pump efficiencies heating with mini-splits isn't any more expensive than heating with oil.

Also, even the smallest oil boilers out there are at least 2x oversized for code-min 2500' houses on L.I., and ridiculously oversized for higher efficiency houses. Even with buffer tanks and heat purge boiler controls they can't hit their AFUE numbers at 3x oversizing, and without the better controls & system design they can fall WOEFULLY short of those numbers.

I have installed many radiant heating systems on the East Coast. ThermaRay-USA has different products for each application. My panels can be installed in the ceiling (radiant ceiling heat), under the subfloor (floor joist heating), and floor cable which is used in bathrooms etc. You can have a thermostat in each and every room if you like - or you can do zones which covers more than one room on the same floor. Nothing heats up faster than these products and they are the only company on the market that offers a Lifetime Warranty. These products can be put under any floor treatment - even wood floors or carpet. It doesn't have to be bamboo it can be any wood and it does not have to be floating with these products. Not pushing a product but I've been using this product for 30 years without a failure. These products can heat your whole house, not just the floors.