Simulate to Build Greener

I know a lot about how the Mill Creek NetZero Home (MCNZH) will perform once it's built because my computer told me all about it.

HOT2000 is a really useful - I would call it essential - free piece of software available from the Government of Canada.

Basically what you do is enter the walls of your house, including doors, windows, and other factors such as insulation value. Once the house's data is entered, you can run reports on how much energy the house will use. The cool thing is that, since it's Canadian software, there are weather data for all major Canadian cities, including Edmonton. So the program knows exactly what type of climate the MCNZH will be operating in.

The skeptics out there will no doubt question how accurate the program is. A 1999 study compared the simulated (by HOT2000) performance of 45 Canadian homes versus their actual energy consumption. "The average difference [between simulated and actual energy consumption ] for the entire sample was 16.1%". Hey, that's pretty good, especially when factors such as occupant behavior can vary so much.

I found running simulations on the MCNZH provided so much insight. Taking away one of the home's big south-facing windows, for example, costs about 400 kWh of energy per year. And, adding concrete floors to complement the huge windows decreases energy needs by about 1000 kWh per year.

How To

If you know your way around a computer, you can learn how to use HOT2000. I've attached the MCNZH HOT 2000 (.HSE) file to use as a template. Also, one tougher part is how to enter really advanced windows into the program - there are some built-in values, but if you're building an eco-house you'll want the best windows that money can buy. I've attached the ".cod" file. To import the codes, just choose "Editors -> Code Editor", and then open the ".cod" file.

Happy simulating! (cross posted at

HOT2000 Residential Building Simulation Software

HOT2000 in action.


RNZ final May30,07.cod2.32 KB
MillCreekNZHome_Without_Overhangs.HSE9.05 KB

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Another great, free, and easy-to-use program developed by NRCan is RETScreen. It allows you to not only evaluate potentially energy saving measures like changing wall and glazing insulation levels, but has very extensive capabilities in the area of renewable energy technologies (hence the name, RET) like solar hot water, PV, biomass, etc. There's also a very helpful, well-done, and again, free, textbook available on the website that explains how to use the program and walks through examples for all of the program's long list of modules.

The only downside is that the program is essentially a super-mega-gigantic Excel macro, so you need to have Excel to run it.

Here's the website:

Also, for those desiring a little more flexibility, I would say keep an eye on the development of the Energy Design Plug-in for Google Sketchup. For those not familiar, Sketchup ( is a free, phenomenally easy-to-use 3D modeling program that many use to develop building models. The United States DOE makes a very powerful (and, again, free) energy modeling application called EnergyPlus, and they are developing a plug-in for Sketchup that will use EnergyPlus as an engine to do relatively straightforward simulations within Sketchup. The plug-in is currently in beta, follow it's development here:

Sorry about the super-long comment.

Thanks for the comment, Josh. I've fiddled with RETScreen before, but never really understood it. I didn't know about the textbook though. I'll give it another shot.

That Energy Design Plug-in sounds awesome. My builder created our home in Sketchup (the pictures I posted are directly from the program). Probably not as useful as HOT2000 for Canada-based projects. The gold in that program is the weather files that have data for exactly where you live.

Also, I'm not sure if I would call Sketchup "phenomenally easy-to-use". For people with good spatial/design sensibilities, maybe. I'm useless with it, though :)

I tried comparing vinyl triple glaze vs. double glaze and the triple glaze ended up with fuel costs more expensive. There seems to be something wrong with this.

The window codes are difficult. I use ones that were made by someone else (saved in the ".cod" file that's attached to this post). I'm not sure what else to advise.


Hot2000 is a good start, but quite misleading in some areas. Go for PassivHaus air tightness levels instead of R2000. (glue/nail OSB or tape seams of foam sheathing and use ADA inside).

Misleading in which areas? After starting with Hot2000, what would you recommend doing?

My suspicion about PassivHaus is that it has been designed and tested in the moderate German climate. They just don't get, for example, three weeks of minus 20 degree weather there like we do, so they may focus on the "wrong" things for our much colder weather.

I described a bunch of the issues with Hot2K in the green building forum (see the link I posted).

Hot3000 is a lot better but is not useful yet (too many crashes).

PassivHaus has it better, even though the design temp is ~-10C. We get a lot more stack effect at -20, which means more air infiltration. Yet R2000 only requires 1.5ACH@50 vs 0.6 for PassivHaus. The PassivHaus work on window construction detailing and heat loss is impressive; unfortunately I found it after I finished building. :-(

Thanks Ralph. Sorry, I didn't see the link the first time for some reason.

I also critiqued the ventilation/air infiltration in this post:

Looking back, despite your suspicions about PassivHaus it seems you built one. Your insulation levels meet the PassivHaus requirements, and your airtightness beats it.
The only questionable area is your windows; I think the frame conductivity might be too high.

I'm trying to use HOT3000 to model different houses. Mostly, the non-rectangular shapes are giving me a hard time. Does anybody know a way of getting technical support (or useful tips from long-time users)? Canmet isn't too quick at answering its emails...

Also, about the PassivHaus, the only thing that doesn't work with it in Canada is the goal of a yearly heating load of 15 kWh/m² with an insulation of only R-36 (which is very good, but insufficient in our cold canadian climate). Also, as they have less sun (and milder temperatures) in Germany than in Canada, they tend to put little emphasis on the use of passive solar.

Hi, Thanks for putting togheter this blog, this is a great resource for me as I am planning my next house with some of theses principles in mind.

Did you had a chance to compare your HOT2000 simulation results against your current energy consumption yet? I would be interested into knowing what was properly predicted and what not.


Thank you for your blog. As others have written, its a great resource as I try to work my way to an energy neutral house.

As a complete Newbie, I am hoping you can point me in the right direction about Hot2000. What did you use to create your custom .cod file? I know how to use the Code Editor within Hot2000 but I don't know how you were able to add fields to the options.

Any help you could provide would be much appreciated!

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