Radiant electric floor heating
Last Post 02 May 2014 12:44 PM by sailawayrb. 18 Replies.
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AjbolitUser is Offline
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27 Apr 2014 12:09 PM
Newbie here - hope you guys do electrical heating systems also.

I have that dilemma for my mountain condo. There is no gas there. Current heating system consist of in-the-floor electrical blowers which I don't like at all - those are old, noisy, not efficient. So the dilemma is - should I do electric radiant floor heating system, or do I just replace existing blowers. Is radiant heating be more efficient than the current one? It can get down to -30 there and split system probably wouldn't keep up, and I wont need AC there anyway. Electric baseboards probably even less efficient. Any other options? Hydronic system wouldn't be cost effective with electric boiler?

While doing my research,  I came to the conclusion that I should just do wire (much less expensive that the mats) - probably thermosoft or nuheat (less expensive than SunTouch). It looks like I should be able to control 5 zones with this upcoming thermostats - http://www.nuheat.com/floor-heating/thermostats/signature.html. Planing on replacing few of the current blowers with the newer ones and keep them as an emergency source of heat - if the temperature drops too quick or my radiant floor failed. I was planing to keep my existing mechanical thermostats for the blowers - put them in utility room - so no one can mess with them. Is there distant temperature sensors that can be retrofitted to work with those old ones (like 30 y.o.) thermostats?  Any other networking high voltage thermostats out there?
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27 Apr 2014 02:07 PM
Based on what you described and considering ROI, I suspect your best option is just replacing your electric heaters. Electric radiant would likely be less efficient and result in higher utility bills than your existing electric heaters. I think your money would likely be better spent improving the insulation/sealing of your building envelope.
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AjbolitUser is Offline
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28 Apr 2014 12:33 AM
Well - manufacturers seems to be agreeing that radiant electric heat is more efficient and cost effective than my current system. Of course all of them trying to sell me the wire ( Was there ever a comparison of effectiveness of different types of electric heating systems? Maybe a book or online forum?
Apparently the guy in the same building installed baseboard heaters - his electric bill went up((
Additional goal would be to eliminate forced air altogether - the only optiom in my application is radiant electric heat, but than again - I dont want to pay even more than it is now on top of expensive installation.
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28 Apr 2014 07:48 AM
You may want consider electric radiant cove heaters. If you place them appropriately, you can use proximity sensors to control them too. Since they are low-mass radiant devices, they can quickly keep people in a room warm when needed and not use much electric when people are not in the room.

http://www.radiantsystemsinc.com/

http://energy.gov/energysaver/articles/electric-resistance-heating

A heat pump heating system would most likely provide the smallest electric utility bill, but likely would have the highest acquisition cost and reliability risk. Electric radiant heat cove heaters would likely be next in line with regard to lower utility cost and would likely have a lower acquisition cost. Again, you should consider both acquisition cost and utility cost, and perform a ROI analysis to see what makes the most sense.
Borst Engineering & Construction LLC - Competence, Integrity and Professionalism are integral to all that we do!
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28 Apr 2014 10:56 AM
It does feel counterintuitive to put those up to the ceiling. One extra reason for the under the floor radiant in my particular case - there is hot tub inside the condo. We might be renting the place on occasions and I can see guys walking to the bedroom in their wetsuits - so we want to do tile floors their anyway, and have those tiles warm would make a difference. Thanks for the links.
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28 Apr 2014 11:31 AM
Well, if comfort dominates acquisition and utility cost, HR radiant floor heating wins every time. However, you started this discussion looking for an efficient and cost effective solution.
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28 Apr 2014 12:13 PM
First, a proper room-by-room ACCA Manual "J" heat load. All discussion precluding such is pure conjecture and a waste of time. If is unlikely that an electric radiant floor would not keep up, (from the information provided) and response time would improve over any air-driven system since water is 3500 times more efficient at moving energy than air.

Response time, efficiency and cost of operation can' t be determined until design temperatures are known. The only way to know the design temperatures is with a the heat load.
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28 Apr 2014 02:22 PM
Is there a way to somehow convert my existing electrical heaters consumption to the square footage of the radiant heat needed?
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28 Apr 2014 02:47 PM
Yes, if done properly, an existing building energy usage analysis would be more accurate than any heat loss analysis estimate. You do need to have accurate heat energy usage data that is broken out from your other sundry energy usage.

http://www.borstengineeringconstruction.com/Existing_Building_Energy_Usage_Analysis_Calculator.html

This would get you accurate whole building heat loss data.  However, you still need to estimate the peak heat load for each room in your building before you can properly design a replacement heating system.
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28 Apr 2014 04:46 PM
But than - given that for the last 30 years that particular building operated with electric blowers without problem - and asuming that radiant heat should be at least as effective - why should I worry about peak heat load? I am planing on installing radiant heat at the maximum allowable surface - its not really that much more money savings if we are to realize that its not needed everywhere. 200-300 sq feet of the wire at the most probably. Besides I would prefer the heated floor everywhere where tiles are installed anyway.
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28 Apr 2014 05:25 PM
You need to design the radiant heat system so it will provide heat gain that will properly align with the heat loss for each room. Not doing so will put you at risk of under/overheating the rooms. The folks selling you on this approach and their product should also be providing you the guidance and information to accomplish this project successfully. You shouldn’t have to ask folks on a forum like this how to properly accomplish this project design.
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AjbolitUser is Offline
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28 Apr 2014 05:38 PM
Given that each bedroom will have its owned thermostat - wouldnt it solve that problem? And I do apologise if I annoy U with the questions - I did try to do my own research, but its obviously not adequate. I will be sitting down with GC this week to go over the project - but how do I know that I can trust his judgement?
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28 Apr 2014 09:25 PM
No, if you manage to install your radiant heat system such that it doesn’t generate sufficient heat gain to overcome the heat loss in the room, the thermostat will just keep calling for heat and the room will never reach the thermostat set point. So your toes may stay warm, but the rest of you may be cold and uncomfortable.

When it comes to hiring contractors, you should hire one well known to do good work or carefully check their credentials before hiring them. Likely the GC won't be doing your heating system work either. The GC will likely hire a HVAC subcontractor and you won't have much choice in the matter. In most states you are considered to only have a contract with the GC and you won't have any say with regard to the subcontractors that the GC hires. If you don't like the subcontractor's work, you can complain to the GC and he may get the subcontractor to do something different. Some better states have contractor regulations that provide a degree of protection to homeowners when things go wrong...and other states do not and you are on your own.
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28 Apr 2014 09:37 PM
Posted By Ajbolit on 28 Apr 2014 10:56 AM
It does feel counterintuitive to put those up to the ceiling. One extra reason for the under the floor radiant in my particular case - there is hot tub inside the condo. We might be renting the place on occasions and I can see guys walking to the bedroom in their wetsuits - so we want to do tile floors their anyway, and have those tiles warm would make a difference. Thanks for the links.


I do not use "Cove" heaters and don't know anyone who does. Stick to your guns. You certainly have input as to the sub-contractors and ask to sit done with them before the work begins. Generals don't generally know much and care less about mechanical systems. An ACCA Manual 'J' is more than a coldest day load, it is the national standard for residential HVAC design. Have one done by a competent professional, if he is a licensed, experienced, contractor all the better. DIY design is always the first mistake.
MA<br>www.badgerboilerservice.com
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28 Apr 2014 09:53 PM
So, who do I look for to do that design? HVAC design engineer? I would probably skip googling " ACCA Manual "J" or "heat gain" and "heat load" and stop here. I just thought that combination of radiant heat and few blowers would for sure keep the place nice and warm. Was told the same by the guys at Thermosoft and Nuheat. But I don't want to make a horrible mistake. Should I start by doing Energy audit, insulate the heck out of the place and than do ACCA Manual "J" calculation (whatever it is) and hire whomever you suggest I should hire to come up with the design of my system?
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29 Apr 2014 08:55 AM
This project is relatively easy and you should not have any problem at all if you hire someone competent. You just don’t want to end up not having enough heat or creating a radiant floor that gets so hot that you need to wear shoes to walk on it. Check credentials. Licensed, bonded, insured with previous customer references is goodness. Even a quick Google search of company name with “complaints” or “problem” can be insightful.
Borst Engineering & Construction LLC - Competence, Integrity and Professionalism are integral to all that we do!
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29 Apr 2014 09:31 AM
When sorting out HVAC contractors, those capable of producing a proper heat load a breed apart. Since most electric floor panels are installed "by others" usually a combination of carpenters and maybe an electrician, a good heat load and simple layout would be in order. The radiant floor vendor should be able to refer you. Hot feet are not generally a concern with any radiant floor system unless you have a habit of leaving the windows open or your loads are extraordinary.
MA<br>www.badgerboilerservice.com
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30 Apr 2014 05:47 PM
As predicted - my GC had no clue to where to run and whom to speak to in regards to electric radiant heat flooring. He was under assumption that I just want warm floors - and keep my current blowers. So do I look for another GC or do I just try and call local HVAC people - where do you find someone who is able to come up with the HVAC design?
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02 May 2014 12:44 PM
Again, no surprise there... Hire someone local from your state who has good credentials and references.
Borst Engineering & Construction LLC - Competence, Integrity and Professionalism are integral to all that we do!
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