Replies

1. 
   BillHartmann | Jul 26, 2002 05:00pm | #1

   Radiant heat is just one way supply heat (energy) to a home.

   How much energy that you need depends on how the size, design, and insulation of the home.

   There can be many sources of that energy. You have chosen electric.

   "Can this type of system really heat the whole house as the manufacturers claim without the meter wheel hitting Mach 3?"

   I don't have answers to you other questions, but first you need to figure heat loses. That will determine how much energy you need. Then you need to find out what you electric rates are. In some areas they are 20 or more cents per kWh.

   Where I am there is a winter electric heating rate that gets down to 3.3 cents kWh.

   You could also do the same thing with hot water radaint with a wood boiler and/or a propane boiler.

1. 
   Otterson1 | Jul 27, 2002 07:12am | #2

   Bill,

   I understand that the design and insulation of the house are going to be the biggest factors in the effectiveness of any heating system, and my winter electric rates are approx 4.5 cents/kwh in the winter.

   My primary concern now is finding the most realistic and cost effective secondary heat system considering that anything I do will be a retrofit of an existing structure.

   The primary advantage I see with using the electric mats, is that I can install them over the existing subfloor (1x12 pine laid diagonally over 2x8 rough-sawn joists 16 o.c.).  Am I right in thinking that a water based system would have to be installed below the sufloor and therefore be laced through the joists?

   I guess my main question is, does using the heat mats over fairly large areas of floor make sense verses the difficulty of installing a water based system in a existing structure?

   Has anyone used this type of system, if so which brands and what results?

   Thanks.

1. 
   BillHartmann | Jul 27, 2002 10:06pm | #3

   I don't know anything about using the electric grids for that type of application. Most suppliers only recommend them under tile.

   But I did run across one (but I don't remember who) that had one that was 5 watts/sq ft (while the ones for tile work was 10) that was suppose to work under vynal and maybe carpet. I my application is for some long term "thing about" so I did not get into the details.

   If the manufacter spec's that application I don't see why it would not work. But you really need to be carefull of the details. Specially the type and placement of fasteners.

   There are a couple of different systems for hot water retro fits that go on the top. They are basically a subfloor with routed channels for the tubing. I think that "warmboard" is one brand.

   For under floor retro fit the tubing does run the lenght of the joist and then a hole is needed to cross into the next bay.

2. 
   TLRice | Jul 30, 2002 03:53pm | #4

   Jesse,

   I have two different manufacturers electric floor heat installed in my house. My home is primarily heated with forced air. We keep the air temps low 60 - 65 most of the winter. The master bathroom tile floor is heated with the Maxxon Infloor cable type. This was the cheapest I could find 4 years ago. It works well, but is a pain to install. The other installations (3) I have are the NuHeat mat type. Much easier to install, but cost more.

   The controls for each are different. One, the Infloor, controls the floor heat based on room air temperature. Turns the floor on and off and heats it to a preset maximum surface temp. The controls are simple, no programmimg available.

   The other (NuHeat) controls the heat soley by floor temperature. The controls have 4 automatic, programmable modes and a manual mode.

   Each floor requires a separate circuit, in some cases GFCI. Nuheat controller includes GFCI. The Infloor system I have does not.

   It is almost always expensive to heat with electricity. The installation of this type of radiant floor heat is the easiest that I know of. You will have to weigh the ease of installation with the cost of electricity.

   When my nighttime set back temp is 60 degrees and I walk barefoot on the 77 degree tile floor, I am always glad I have them installed.

1. 
   Otterson1 | Jul 30, 2002 04:15pm | #5

   Tim,

   Thanks for the info.  How big are the floor areas where you have it installed?

   Also, how many watts does each system pull and what size circuit did you run?

1. 
   TLRice | Jul 30, 2002 08:23pm | #6

   The Infloor system heats a floor area of about 6 x 11, produces about 800 W of heat, in a room of 130 sf. Manufacturer recommendations were to use an individual, 20A circuit, which is how it is installed, though at 120 V, 800 W is less than 10A. The other three are various sizes ranging from 40" x 60" to 40" x 120", all less than 800 W (I don't really recall, I have the specs on each at home, the NuHeat mats come in standard sizes, with heat output data available on their website http://www.nuheat.com). I have two rooms, each with a separate mat, on one circuit, one controller (the NuHeat controllers will accept two loads). Another room has a separate mat and controller. Each controller is supplied with an individual 20A circuit, again per manufacturer's installation instructions. Check out the website and the sizes available. The sizes are for clear floor areas only, you cannot install the mat under cabinets (don't know about furniture) or other fixed objects.

2. 
   nigelUsa | Jul 30, 2002 11:22pm | #7

   Check out http://www.warmlyyours.com they are very helpful and the price is very fair. I have used their product on a few jobs and the people are very happy. Just send them drawing and they will plan it all for you.