Zoning radiant heat

Annie Hall

I am now comparing two bids for installing a hydronic infloor system in my new house. Both bids are fairly comparable on price, but the installation plan varies as follows: Installer "A" uses 1/2" tubing and plans to install on 6, 8, and 12" centers. They plan to install 6 zones (downstairs living space, which includes kitchen, living and dining) and then upstairs basically each bedroom and bathroom would be an individual zone with its own thermostat).

Installer "B" uses 3/8" tubing and 6 or 8" centers. They call out three zones, or, as they call them, "primary loops" with thermostats. Each room in a particular "primary loop" would have a valve we could manually adjust to trim heat in that particular space.

Both installers are very reputable and have done many installations in our area. Is there an advantage to one installation design over the other, or, as they say, is there "more than one way to skin a cat"?

CG_2

zones

You may well get hundreds of opinions here on this subject, here is mine. Of course we all know a heat loss analysis is needed from there all conmponets can be sized and calculated. To the exact zone question it all depends on what you want to spend, more zones more money [ time and material ] Zones really depend on many factors, north and south facing, heat loss criteria, room sizing and layout. I like the fact of the first quote and his zoning. I often zone off, especially a master bath and bed, the bathroom from the bedroom. People tend to like to sleep in a cooler enviroment and when they stand half naked in a bathroom like to feel warm. The easiest way to accomplish this is with zoneing, the most control with the least effort. The second quote you recieved required someone as I understand it to manually adjust valves to balance out the system, well from fall to winter to spring, sunny to cloudy I would not care to be adjusting my zones from time to time. I would prefer the system with the least interaction. Of course we live in a world of communication problems so how I have interpeted your letter may not be what the contractor is implying, however, this will give you one opinion and a place to gather more information. Keep talking to your contractors asking questions until you fully understand what they are giving you and then use common sense.

Radiant Wizard

Zoning

I would need more info. How is the radiant being controlled? How many manifolds? What water temps are needed for each particular room? Is solar gain an issue in certain rooms? Are all the floor coverings the same? Sounds like this is a staple up job. Are plates being used? Why? Floor response time. This is what gets people in trouble when zoning. It sounds like installer "B" is utilizing plates and installer "A" isn't. 3/8" Tubing is the more practial used tubing when doing staple up. It's easier to work with and you get out the same amount of but's. The only think you give up is loop length. But you want your loops even as possible within each manifold. As Johnni 5 says, "Need more input."

Annie Hall

A bit more information on our project

Both contractors are planning to use tubing in gypcrete. Our floor coverings will be the slate/hardwood in the living area and carpet/linoleum in the upstairs bedrooms and bathrooms. The one with the most zones (6) is using a Tekmar 363 control system. The one with the fewest zones proposes "three Honeywell zones with all equipment including manifolds (Infloor) and thermostats for easy balancing and room by room control". Both include an outdoor reset.

I don't have much information about the underlying calculations they used, although I am sure they haven't done a detailed design yet.

Annie Hall

I think you understand it correctly

Contractor B is providing manual valves so that, for example, the master suite would be a zone with one thermostat and we'd manually pinch back on the flow to the bedroom so that the bathroom stayed proportionally warmer than the space where we like it cooler for sleeping. Contractor B claims that we would set these to our preference and then rarely if ever have to adjust them.