Hello, First of all, let me give you a bit of context on our construction project - which will be about an hour north of Montreal, Quebec, Canada. Next April, we'll start building a 1,500 sqft garage with a 1,300 sqft loft on top of it. Near September, we'll build the house that is 25 ft in front of the garage. The basement will be 1625 sqft, the first floor will also be 1625 sqft and the second floor will be 1150 sqft. So we need to heat about 7,200 sqft during winter time. One very important thing to note that we'll be completely off the grid. We'll have a 60 KWh battery bank with 12-15 KWh usable per day. Both the house and garage will be well insulated (R24 for foundations, R29 for walls, R60 for roof). We are considering a wood pellet boiler for heating - something like a Froling P4 32/38 with a 200 gallons buffer tank. The boiler will be located in the garage - and highly insulated piping will go from the garage to the house (buried 8 to 10ft deep). For the concrete slabs in the garage and the house, hydronic radiant floors is a no-brainer decision. Where we hesitate a bit is regarding hydronic radiant floors vs. low-temperature radiators (like Myson and others - there are beauties out there!) for the loft of the garage, the first and second floors of the house. It seems to me that radiators would be less complex, less expensive, offer a bit more control and require fewer circulators - which is very important for us because we'll be off grid. Also since the house will be well insulated, the heating requirements won't be big. I would like to have your input on this - the pros/cons of going all radiant floors, or a mix of it with radiators. Thanks!

We like the Myson radiators and they have been successfully used in England for many years and I imagine in Canada too. They are well suited for zoning locations where the desired indoor temperature will be frequently varied (e.g., locations that don’t always need to be fully heated). As you indicated, HR floors is a no brainer where you will be pouring concrete slabs and don’t need to frequently vary the desired indoor temperature. Cheers!

Anyone else would also like to pitch in their opinion? Unfortunately everyone I speak to wears a sales hat and pushes for his/her solution.

If you are going to get the condensing boiler heat exchanger option, then there is an advantage (maybe 8%?) to the lowest possible return temperature. Also consider some use of a co-generation propane or diesel generator.

Hi Jonr,

Thanks for your feedback. We indeed plan to have a propane generator. As for your comment considering the of a condensing boiler heat exchanger, I haven't made my mind around this. In any case, I don't think it'll have much impact on the whole design, doesn't it?

Thanks!

Posted By extrafu on 22 Dec 2016 09:22 AM
Anyone else would also like to pitch in their opinion? Unfortunately everyone I speak to wears a sales hat and pushes for his/her solution.

Not alot of difference out here, place is packed to the brim w/sales hype. What is your heating and cooling load? What size PV gets you off grid? What is winter time PV production or post a monthly graph? "7,200 sqft during winter time" thats quite a bit.

With that much SQ/FTage I would definitely look to maximize insulation and a cogen plant to keep the batteries in a happy place during the winter and harvest the waste heat off of to help heat the place... As for heating, radiators for the part-time loads might be best, although a low mass/above floor radiant option having a faster response time might work just as well for you...

Note that for the garage/loft, the heating requirements during winter will be of course lower - especially for the loft as we won't have too many guests visiting us.

The PV system will be composed of 24 x 280 Watts panel. We plan to have 12 Trojan IND23 4V batteries, each with about 1300Ah capacity (62 KWh capacity, 50% usable, so about 30 KWh). We estimated our daily usage at 9.5 KWh right now, with 2 circulators and the Froling P4 38KW pellets boiler (and of course, everything else in the house that needs electricity). That will likely go up a bit if we add more circulators.

Assuming you don't know what your kBTU/hr heating/cooling loads are? It should be one of many parameters tied to PV output and battery sizing. DOE BEOPT is free and does a decent job at this & much more including occupancy rates based on building America stds.....It's pretty easy to use and has most USA TMY3/2 weather files including CAN, three towers in Montreal. If you are interested I can walk you though it or their video tutorials and forum are good. I'm doing a loft design now only about 2100 SF. Like you I don't trust sales hype contractors so I do my own then have them dbl check me. HR is not always a "no brainier". BEOPT is present and future value optimization model that actually calculates $$$ based on a lot of whole building factors including mortgage & discount rates, inflation, M&L, ACH, etc you can optimize and compare including manual j/s HVAC choices. Component cost is already loaded in and you can modify all the parameters. Outputs hourly, monthly, annual utility bill in D-View you also down load. You'll never get this level of info to base costly decisions on out here.

Hello Extrafu, do you about Thermaray heating panels? Those guys have a great solution for heating. One of the solutions they offer is underslab heating panels. They are meant to be used for off-peak hours to build thermal mass and heat the area above it at low cost. Since you are going of-grid, that might be a great solution, as I believe, it works with AC or DC sources. So you can reduce your battery system, and build thermal mass during sun shine. The thermal mass can last somewhere between 3 - 5 days. I would recommend you give them a shout, they do have a distributor in Quebec close to you. Here is their website:

www.petrabuildingsolutions.com

I heard about them through a friend who is very satisfied with his system.

Hi Rizeq,

Thanks for the information you provided. Unfortunately, being completely off grid, heating with electricity is a no-go.

I am considering a pellet boiler. I have two models in mind right - the NBE/Kedel RTB or the EkoGren EG (http://ekogren.info/pellet/).

While I found a good amount of information on the Kedel KTB, I have found little to none about the EkoGren. Both are available in Quebec.

Thanks!