Hey guys. I am new to the whole radiant heat industry. I recently purchased a home and I am renovating. I was looking to do some heated floors but I am from a small town and I cannot find any one to help. I did so research and came across some software that is supposed to be very easy to use to design your heating system. I was just wondering if anyone has any experience with either of these two programs and could help me decided. The first program is LoopCAD from www.loopcad.com and Right-Suite with the Right-Radiant Plus Add on from http://www.wrightsoft.com. Can anyone shed some light on these two programs. Thanks in advance for your help.

Hi Clay,

Those are both pro-caliber programs, but two things come to mind. To be clear about my bias, I design radiant heating systems for a living, so take that for what it's worth.

1. GIGO, garbage in, garbage out. If you know something about heating or hydronics you might be ok, but these are just programs to help a knowledgable person do a design.. if you are not knowledgable, it is still possible to make big mistakes during the load calculation or in decisions after that.

2. That is a very expensive software suite (wrightsoft). It's very good, probably the best or one of the best, but you're going to pay for it, for sure.

well, loopCAD is just a drawing software, I believe, to make doing tubing layouts easy. Wrightsoft is a true heat load calculation and system design tool, typically used by supply house engineers and such.

NRT.Bob,

Can you shed some light on an issue I have with my HVAC man? I'm getting ready to build an ICF house, 2200 sq ft inside the walls, using Roth radiant panels in the floor. I did a heating/cooling load calculation using the "HVAC for Concrete Houses" s/w from the Portland Cement Assoc. I come up with a heat/cool load at 19,000/17,000 BtuH.

My HVAC man, a nephew-in-law, uses the WrightSoft suite. I was going over his calcs yesterday with him at his office, and everything seems correct with his inputs, meaning the window data, wall sizes, roof type & orientation, etc is the same as I used. I was almost shocked at the detailed inputs WrightSoft has. However, he is coming up with a heat/cool load of about 40,000/24,000 BtuH. The cooling isn't way off from my calc, but his heat load is double.

I noticed that the WrightSoft program doesn't have a clear option for sealed conditioned crawlspace (built-in in the PCA program) nor for conditioned attic with insulation on the roof. Stan input a conditioned basement of 4' height, and a vaulted ceiling option that somewhat equates to insulated roof. One thing that has me scratching my head is WS says I have inadequate exposure diversity (AED). I have a hard time understanding that one since I have a lot of roof shading on sw facing windows. But that wouldn't impact the heat load side of the equation a whole lot anyway, I don't think.

Any ideas why there might be such a descrepency between the two programs? Could it be, as PCA touts, that Manual J does not adequately account for the thermal mass of the concrete and the time delay in the heat transfer from out to in, which the PCA program does? The fact that WrightSoft is no slouch of a program, and that it is so different from the PCA result, really has me puzzled.

Would it worth the $50 to buy the one time use of HVAC-Calc for a comparison? I used it a couple of years ago for an AC replacement. It worked good, but that was on a frame constructed house.

The PCA s/w heat load is in line with what I have heard or read commented about in other ICF houses.

It's very hard to say. PCA could be overstating the mass effects. Your "fudging method" for the crawlspace or attic could be off... if, for example, you are figuring the crawlspace as if it were a fully heated basement, that may overstate the heat load down there. Manual J does overstate things, I believe. Part of the GIGO thing I mentioned before is knowing that sort of thing ;) Personally, I'd expect it to be somewhere in the middle (I don't fully trust "mass effect" calculations). You may find your heat source has the wiggle room for the higher value anyway, though.

I'd like to see what the PCA is using for a 'Thermal Mass' calculation. Also, consider that they might be a tad bit biased toward concrete(ICF's).

What I would check 1st is the R-value of the walls that the PCA program is using. It is what the manufacturer indicates that it is. Not some 'effective' R-Value. Heat Loss calculations are pretty straight forward, and not near as complex as Heat Gain. We have one that you can use for free at PanelCrafters.net. Why don't you try it and see what it tells you(Heat Loss only).

Here's a quote from the PCA web site about the s/w.

"Based on this, the Department of Housing and Urban Development (HUD) sponsored an effort to compile available information regarding energy use in concrete homes, develop additional information as needed, and use this information to develop a methodology to properly size heating, ventilating, and air-conditioning (HVAC) equipment for concrete homes. HUD supports insulated concrete construction because it is energy-efficient and affordable. The result of this effort is an Excel-based program intended for use by residential contractors to estimate the required heating and cooling system capacity for single-family concrete homes. The capacity is based on a user-defined thermostat set point, the house dimensions, construction materials, and location (US and Canada). The software uses the DOE2.1E hourly simulation tool to determine energy loads for equipment sizing."

It's my understanding the DOE 2.1E s/w is no slouch of a s/w program, and is quite complicated to use. It was written with commercial buildings as its target. The PCA s/w is a simplified front end for concrete homes.

For 11" ICF (6" concrete) walls it uses R22. The big difference is it calculates heating & cooling on an hour by hour basis using 10 year mean hourly temperature and humidity data, not the max and min design temperatures Manual J uses. One interesting contrast is it calculates, in my case, the heating and cooling loads to be about equal, whereas Manual J shows the heating to be twice the cooling. I ran the numbers on the Panelcrafters program. They were roughly the same as the Wrightsoft numbers. Not suprising since both are Manual J based. I also bought the two month version of HVAC-calc to see what it shows. The author told me several months ago it takes into account thermal mass of concrete walls. I used it a couple of years ago when I replaced the AC unit in my home i Louisiana. Results were great. Down sized from the original unit and worked better.

Mac

I recently did a full remodel on my 4,000 square foot home. I live in Provo, Utah so we have cold winters and radiant heating is not a strange thing to have. I installed systems in my master bathroom and basement floors and never looked back. The systems are so convenient! I love them! The company I used was Heatizon Systems. I'm not sure about your area but they have distributors all over the country. Their Web site is www.heatizon.com so I'm sure you can find more info there. Good luck!

I don't know about software but i had those guys come and do it for me. its great to have. you can learn more about it on www.radiantheatingny.com

We use Wrightsoft as our primary heat load software and have reviewed all currently available software. We are also Uponor certified and use their module for most of our radiant floor heating
and snow melting designs here in Minneapolis. The learning curve for radiant heating and cooling software - and design for that matter - is a steep one. Most regular "HVAC" contractors have no
design training for HVAC let alone radiant floor - a small fraction of the industry - and most are not licensed.

For the novice or professional to buy Wrightsoft or LoopCAD for a one time or even occasional use is a waste of time and money. Most of our design work - both local and around the US
and Canada is done for less than the cost of software and backed by 25 years dedicated radiant design and installation experience and formal factory training by various manufacturers
of PEX tubing such as Uponor and Viega, and certification training for Wrightsoft.

Since every radiant floor heating system is a custom design, cookie-cutter software is of limited use.

For professionals LoopCAD is good if you specialize in radiant floor heating as we do, but Wrightsoft has the full sales package with radiant floor plus Manual 'D' and commercial modules
we use increasingly in larger, more complex home and light commercial HVAC designs that include air handlers for AC, ERV's and snow melting.