For a cooling load analysis, the latitude and orientation of the building and the time of the day make a great difference in the solar heat gain and this should be considered. So if you are doing a cooling load analysis, you should use our cooling load analysis software instead of our heat loss analysis software:

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

Maximum solar gain and cooling load will either occur mid-morning or mid-afternoon and you should evaluate both cases to determine your maximum cooling load. For a heat loss analysis, maximum heat loss will occur when there isn’t significant solar heat gain, so this isn’t a significant factor.

If you are doing the building preliminary design, you should also consider using modelling software to gain an appreciation and better understanding of what is driving your heating and cooling requirements. This allows you to better design the building to minimize the heat loss and cooling load BEFORE you size the heating/cooling system.

Thank you again for the great info.
Yes, we'll need to consider the effect of the skylight on the load. If we make it operational, it would be great for summer ventilation, but I can see how it would be a big source of heat loss in the winter.
We'll be selecting a builder very soon, so I hope to find one who understands energy implications of various insulation levels and corresponding HVAC design.

sailawayrb, I haven't worried much about the cooling load since in our climate we get 230 cooling degree days (Fahrenheit) per year and that's using 64F+ as the temperature boundary. I'll look into that if I get a chance, but I hope that we should be able to keep the house comfortable and suffer through the two really days we get here every year.

Your calculators are immensely useful. I haven't had the time to calculate an expected climatic heat gain yet, so without it, so far, I've managed to put together the following comparison to guide our decisions on investment in the building envelope:
My baseline (building code minimum) envelope is:
Walls: R19
Ceiling: R40
Under slab: R10
Windows: R3
Doors: R5
ACH: 0.25

This minimum envelope gives me the following:
Design heat loss: 18,660 BTU/hr (~11.3 BTUs/hr/sqft)
274 BTU/F/hr
Annual MBTUs: 44.77
Annual kWh: 13,113
The value of that energy @$0.14251 is $1,868.73 annually.

When I "upgrade" the envelope to:
Walls: R25
Ceiling: R50
Under slab: R20
Windows: R4
Doors: R5
ACH: 0.25

I get the following:
Design heat loss: 14,834 BTU/hr (~9 BTUs/hr/sqft)
218 BTU/F/hr
Annual MBTUs: 35.62
Annual kWh: 10,433
The value of that energy @$0.14251 is $1,486.81 annually - a $382 savings/year.

Going to R40/R60/R20 structure gave me a further reduction of 1000 kWh of energy annually. I'll see what the cost of those upgrades is and then plot my ROI.

Note that I have ommitted the attached garage (keeping it unheated and using only as-needed space heater) and the 4x4' skylight on the western roof slope (could be a big source of heat loss) from my calculations. As well, as noted above, I don't have any climatic heat gain in the numbers and I think the slab will contribute some thermal storage on certain days.

That said, it looks like a low heat load house according to these calculations even with an "OK" building envelope.

More calculations are needed, but I'm starting to think about the following:
- wood fireplace as a backup on the coldest days
- solar thermal DHW with solar thermal tank storage feeding a low-temp distribution system
- electric boiler backup connected to time-of-day tariff (7 cents/kWh 11pm-7am)

I'm still researching other energy sources and have come across another air-to-water heat pump unit: Thermo Matrix CoolFire. The pricepoint is attractive compared to the Altherma at almost half the cost, but the lowest nominal output unit is a 3-ton pump, which would be an overkill given my heat load numbers above. That said, if it's the same price as the solar DHW, I might as well use that HP system.

Eljay, we are glad that you found the info and our software to be useful. It sounds like you are learning and making good progress.

TCP, we have not found CMASS to be at all accurate for predicting thermal mass performance. It is more akin to being a fudge factored, rule of thumb based approach as opposed to a validated first principals math model based on physics. If you are referring to John Siegenthaler’s Hydronics Design Studio, YES it is a very useful suite of software for accomplishing heat loss analysis and designing hydronic radiant systems including proper sizing of buffer and expansion tanks. While the software on our website doesn’t have nearly as easy-to-use graphical user interface as Hydronics Design Studio, our software does allow one to accomplish these same design tasks, is more powerful in some areas, and is free to DIYers. We validated our software against Hydronics Design Studio several years ago and we discovered some minor bugs and errors in Hydronics Design Studio that John acknowledged via email and subsequently corrected. We actually prefer that our software requires some knowledge and depth of understanding in order to use it. Often times when you make design software simple to use, it may get badly used by less than competent people.

Sailor, we have CFD and FEA VERY expensive software along side a multi-millon dollar test lab here with a world class hot box, shaker tables, fire test, endurance fatigue test, and mounds of world wide field data to calibrate the models that are very accurate but yet still not perfect. I asked before you did not respond, show me how by test and field data your model is calibrated to climate zones in the USA? I'd like to see a test report. I write them and interpret this sort of data everyday for the past 30 years, so if anything I am 'competent" you just have to show the data to prove you and your calculator are since I KNOW the basic load calculators can not perform. Show me a actual build you produced using your calculator then show me a tested instrumented build that proves it accurate. This should be no biggie since you should calibrate your models and calculators. This is EXACTLY what ORNL did. Your words do not make their efforts wrong and worthless, nor John's, sounds like a sales pitch to me. Looks like John has no phone contact or support forget that too. People should know you get what you pay for in life.

Sorry TLP, we don’t publically share the details of our R&D efforts as it can have an adverse impact on our IP rights. It sounds like you have everything figured out anyhow, so not sure why you would make such a request. Our DIY software and the advice we offer on this forum is free. If you don’t like our DIY software or our advice, please don’t use it.  In fact, if you are a commercial enterprise and you use our DIY software without first getting a license from us, you are in violation of our software agreement terms of use.

John’s company is Appropriate Designs and his contact info is on his website. For Customer Support or General Information, email [email protected] or [email protected] respectively.

Posted By sailawayrb on 27 May 2014 10:22 AM
Sorry TLP, we don’t publically share the details of our R&D efforts as it can have an adverse impact on our IP rights. It sounds like you have everything figured out anyhow, so not sure why you would make such a request. Our DIY software and the advice we offer on this forum is free. If you don’t like our DIY software or our advice, please don’t use it.  In fact, if you are a commercial enterprise and you use our DIY software without first getting a license from us, you are in violation of our software agreement terms of use.

John’s company is Appropriate Designs and his contact info is on his website. For Customer Support or General Information, email [email protected] or [email protected] respectively.

Right, I know better to swallow free software that has people looking at a website for sales purposes. If you are going to do that put your disclaimers out here and make them clear! Please stop bashing some of the best labs like ORNL in the industry that DO share good data since they have nothing to hide or profit from.

TLP, you will note that we include our company name and logo on every post that we make to this forum. We are indeed a “for profit” licensed professional engineering and construction company. Our company website contains detailed information about our company including our affiliates, credentials, disclaimers, and website terms of use. We do not hide behind the anonymity of only a vague user name. We are big fans of ORNL and only commented that we found their CMASS software to be less than accurate. If you believe otherwise, you are free to use it. You are also free to create better software tools and make them available for free like we have too.

Sail, let me help you with interpreting data like the CMASS calculator. That data is only accurate to the actual prototype builds that were used to calibrate the models/calculators. You can look at the number of builds in the EXTENSIVE test report. The extensive modeling that resulted from builds, or that data is accurate but, not as accurate since it does not know all the variables, assumptions are made noted in the report, read it. For example, 4" of interior concrete was shown to be more effective than 2 and quantified by a higher DBMS one could put a COP to based on concrete vs stick prices in their area and CMASS results.....ICI more effective than CIC. Those are what you take away from it and whether or not it makes sense to stick or mass build in your region. Due to the number of ACTUAL builds that captured the regional data to be "interpolated" it will be more accurate than basic load software, no doubt!! Especially when there are complex fluid dynamics. What exactly did you correct in the CMASS calculator, or, are you not allowed to disclose that too? I have talked to the Director there extensively. I'd like to call him back, or perhaps I will anyway since I want to know about these "errors" you 'corrected" that validate your comment, "not found to be at all accurate" Makes me wonder why it has not been taken down, they have a name, a global one at that, to protect too? By the sounds of it you are saying they are wrong,

" we have not found CMASS to be at all accurate for predicting thermal mass performance"

So I guess we are all to take your word over real data you do not provide? Common stop being silly! The CMASS is accurate to the level of instrumentation, modeling, and Engineering used and a MAJOR lab stands behind. I'd say it is accurate and people should run the calculator, read the test report, and get a good understanding of mass so they are not distracted by free calculators that have no proof of being accurate. We are too busy locally to have a need to put a bunch of calculators on our site that don't work. Most companies do not have or will not incur the cost of massive builds and data to be a world wide place for answers. That is making some large claims at others being wrong (ORNL, ETC) I'd like to see validated.

TLP, kindly reread what I wrote… The errors we discovered were associated John Siegenthaler’s Hydronics Design Studio software and NOT with ORNL’s CMASS software.

However, we stand by our statement that “we have not found CMASS to be at all accurate for predicting thermal mass performance.” We prefer design software that uses applied engineering principles to accurately predict how a design will perform BEFORE it is constructed as opposed to a simplistic software database that is developed and refined AFTER something is constructed.

We are not in the business of publishing engineering data, providing engineering training to novices, or validating the design approaches used by other engineering companies. If you don't have adequate engineering knowledge to start with or you just feel the need to accomplish more testing to gain more first-hand knowledge, that’s what you should do. Like us, you should also consider listing your professional engineering credentials on your company website if you are truly concerned about full disclosure and engineering credibility.

Posted By eljay on 28 Apr 2014 08:02 PM
Regarding solar, I have attached the proposed hip roof line as opposed to a gable roof and showing the orientation of the house.


The yellow areas I think are the only ones were I can think about solar panels in the future. On the front (left) is a garage attached on the main level, so I'm sure half the roof will be in shade for significant portion of AM sun. The yellow area on the larger roof is 144 sqft in total (SSW orientation), so I figure it will hold two 5x3' 250W panels. The thermal panels from a local supplier are 4x8', so I could likely only fit one on the garage roof for DHW. That's not much of a solar potential. :(

It is a small lot (50x100), so I don't have much freedom on house orientation and the back yard is already small.
Given those constraints, is it worth making the house "solar ready" now (wiring, roof terminals etc.)? I'd like to say 'yes' because I'd love to have it but don't see much potential in that drawing beyond DHW solar unless you fine folks can suggest a design change that will work (btw, having a gable roof running left to right would look very odd in this neighbourhood).

Hey eliay, the content shared by is very helpful to me.... Thanks for sharing......

do you have any elevations of the house, plans showing the house on the lot, and photos of the neighborhood? Personally, I've always felt that doing something that is against ones' best interests because of "what others may think" is short sighted. But having said that, it's hard to make suggestions without knowing the context.

Posted By sailawayrb on 27 May 2014 03:30 PM
We are not in the business of publishing engineering data, providing engineering training to novices, or validating the design approaches used by other engineering companies. If you don't have adequate engineering knowledge to start with or you just feel the need to accomplish more testing to gain more first-hand knowledge, that’s what you should do. Like us, you should also consider listing your professional engineering credentials on your company website if you are truly concerned about full disclosure and engineering credibility.

This one made me laugh, the icing on the cake. You have a world class engineering firm that has redefined history!

“If you don't have adequate engineering knowledge to start with or you just feel the need to accomplish more testing to gain more first-hand knowledge, that’s what you should do. “
Need to test since we don’t have ‘adequate engineering knowledge’ knowledge to start with or, you just feel the need to accomplish more testing to gain more first-hand knowledge?

So I guess what you saying are all the labs such as ORNL and BSC that need to test don’t have the Engineering expertise you do? You know, you should not be in the building industry you need to be a rocket scientist, with your vast knowledge you could fly homes to Uranus ;)

Just yesterday we have exhausted the models, calculations, to the best of our knowledge and this happens all the time across the world we hear from our clients. The test fixture we build to simulate the actual environment (thermal, pressures, CO2, etc) failed our part The models and calculation were wrong. That does not mean we do not know what we are doing, nor ORNL and BSC since they do hot box testing, nor WUFI to calibrate their models, nor the rest of world to capture their mistakes and lack of knowledge. We don’t have to look far into history to see that formulas are not all that is needed. So we are adding some stress/strain gages to validate our calculations and get a check on reality.

Of course we could develop a new design without the bench test (which by the way is how code requirements for materials are developed, for one) with our clients doing the “field” test trials and errors around the globe and our client could continue to pay the maintenance and failure cost. This happens often, companies that cannot afford the R&D testing put the product out for field testing by them.

Here is some advice for the reader, if an engineering firm wants to sell a design or “smart” software, or their great services they will stand behind it by signing a contract that rebuilds the building should it not perform. The performance spec should be defined in detail and have your attorney draw up the contract. Often you find wording for engineering and contract services to protect them, that work is performed in a ‘workmanlike manner’ or to “industry standard”…here there is no standard when it comes to design-to-mass. ORNL by DBMS are attempting to develop those standards and code but, we still do not see a standard or code or calibrated model that tells os where and how much mass do we need in thickness or how much a builder has to spend on concrete, etc….. You cannot calculate accurate heating and cooling loads until the calculator has a COMPLETE understanding of that mass.

The best source is local, perhaps a builders association with some mass builds in your area. There you could find out mistakes that may or may have not been validated by and Engineering firm and/or HVAC pros. Some of the mass parameters needed are density, specific heat, heat capacity, solar inputs, moisture inputs, mass depth inputs, flux directions, etc….as you can see there are a lot of variables there, add the massive variables of the climate zones and it can get quite complex. Modeling such as WUFI that has been calibrated to actual builds still struggles. Our models are ten times better and struggle, our test don’t lie.
Outside of that a good builder can sequence the build and determine the load after the build, including ventilation. The only thing you really need know up front is what and where the lines are going to be ran and where the unit will be located. If it makes sense and it does not cost too much put the lines in for the roof panels. In my design, I know I have to run lines on some of chases I have, Once the walls are closed up it is too late. Not a good idea to design without the input of a good builder, or better yet design-build-test is the best approach. Keep it local you’re best resources for design and build are probably in town.

Here are the r-value requirements for Energy Star Certification. Take note of the low value for mass. It needs a DBMS value not a low r-value. The rater could use REM software, the owner after build could find the mass wall bridges or needs a foam core depending on several design parameter deltas between the interior and exterior wall surfaces and depths of the mass, and many other factors the REM load software failed to capture.
Energy Star: Certified Homes, V3 (R7) Thermal Enclosure System Rater Checklist

1. High Performance Fenestrations(opening’s):

• Prescriptive Method: (modeling not require, no trade-offs) vs Performance. Difference is later uses Exhibit 1 in “National Program Requirements” , an average house size (Benchmark Home) based on number of bedrooms with respect to “Conditioned Floor Area” (CFA) (EG: 3/2200, 4/2800). If home is 3 bedroom or larger Performance must be used. See note 7 for bedroom definition, 8 for basement CFA. All Certified Homes must pass 4-test; Thermal Enclosure, HVAC(Contractor & Rater), Water Management, see checklist.

2. Quality Installed Insulation (See 2009 IECC Ch 4, table 402.1.1) (IRC 2006 is the same)

(Code min, do better , Simulated Performance Model : REM Design/Rate, Enerygage (Hire or DIY)

• Mass Walls R-Value: 5 (10 if more than ½ insulation is on interior, see footnote 1 below)
• Wood Wall R-Value: 13
• Ceiling R-Value: 38 (R-30 if full height over top plates, see note 3 checklist)
• Fenestrations: .60 U-Factor
• Glazed Fenestrations(SHGB, see note 3): NR
• Floor R-Value: 19
• Basement Wall R-Value: 10/13 (see note 2)
• Slab R- Value and Depth: 10, 2 ft
• Skylight U-Factor: .60

1. Per pg 1, Inspection Checklists: Rater is expected to use theIr experience and discretion to verify that the overall intent is achieved. If uncertain, Rater can check with their Provider first then report the issue to the EPA for guidance.

TLP, so do you just badly write engineering speak or are you actually an engineer? By that I mean is there actually a state in which you operate that has granted you a license to practice engineering? Cause if the answer in NO, you are NOT an engineer no matter how much engineering speak you badly write. If the answer is YES, post it on your website and I will eat crow.

Hell no I'm not an Engineer, those dummies! I had a drivers license but the cops took it away. Good news you don't have to 'eat crow'. I can't speak or write English either so what

TLP, thanks for your input in your initial post above. I aim to educate myself sufficiently to pose the right questions to all the contractors and challenge them to prove to me that their recommendation is based on some sound principles rather than "how they've always done it".
I think your "battle of credentials" with sailawayrb is intriguing, but I welcome your original suggestion of starting a thread on Siegenthalter's presentation and use that to discuss how to design and prove the points he's making using the various available tools such as the ones you've listed and the ones Borst is making available on their website.
I am not qualified to cast judgement on which one works precisely. I know that even the radiant design calculators on Borst's site are beyond my desires of designing my whole radiant system from scratch. But I find them extremely valuable in my education journey on "how energy design" works, what to look for and what to ask. I know I will not be able to incorporate all of the learning into my house design due to various real-life constraints: availability of local knowledgeable labour, economic/ROI factors, and my wife's patience! So, the end product will be a compromise rather than the best engineering solution. But I am determined to use all this wonderful knowledge I've gained through everyone who has willingly contributed to this thread to drive my decisions.

For example, after talking to two builders, one of them provides a door blower test at the end of the construction because it's needed by an EnerGuide inspection to give the house a rating. They don't do any throughout the build, which is concerning. Another builder has asked me "what is a door blower test?"
Two months ago, I wouldn't even ask that question, because I didn't understand that I can be sending a third of the energy in my electrically-heated house out through poor sealing.

So, again, please keep the contributions coming that will lead me and other newcomers to "green building" principles to drive the right decisions.

Posted By simonedwin on 28 May 2014 01:44 AM

Hey eliay, the content shared by is very helpful to me.... Thanks for sharing......

Glad to hear that!
You may find this site useful to see how the sun moves around your house/site at various times of the year: www.suncalc.net.
It's not meant to be used to position your house etc., but it gave me a good starting point to think about where I'd have big issues with terrain obstacles for solar insolation and how the house would get its light throughout the day etc.

Cheers

Posted By Bob I on 28 May 2014 08:28 AM
do you have any elevations of the house, plans showing the house on the lot, and photos of the neighborhood? Personally, I've always felt that doing something that is against ones' best interests because of "what others may think" is short sighted. But having said that, it's hard to make suggestions without knowing the context.

I don't have any suitable versions of the elevations to post, but generally, I agree with you. At the same time, I have seen some houses in the neighbourhoods that I really like on their own or in a magazine, but on their street, they completely disrupt the "streetscape". And to be clear, the reason we are designing our house from scratch is because we don't like all the new subdivisions that go up with 30-40 houses and a long list of covenants the make every house look the same. So, we are certainly not going to be forced to blend in, but we are trying to strike the right balance between getting the house we want (and we're not looking for a futuristic looking bright orange cube ;) ) in the middle of two regular split-entry house from 1980.
We already fight the battle with pretty much everyone about the fact that we won't have a basement and the house will not be split entry. :)

I don't have a 'battle' with Sailor I just enjoy messing with him :) I wish he was right about testing I sure am getting tired of emails like this by incompetent yahoo test engineers that can't spell or write. :0) "I don’t think strain gages will work for this test, the wires out strain gages have are only rated for 180 deg. F. The Endurance Test runs at 230 deg. F. " I'll start a thread soon as soon as I finish reading it again. These are alot of graphs he shows on the mass subject I will take a closer look at. If you are familiar with FEM (Finite Element Modeling) and CFD (Computation Fluid Dynamic software) you know it can get complex and one model to handle both can be VERY time consuming, at times inaccurate or impossible to capture all the air and heat flow. If you have the means to run what is called a "qualifications test" out of lab or instrument a real build in your climate zone the results will more than likely be more accurate. These models are great for clean sheet designs that have a large r&d budget for Engineering to help clients choose a path of options, and to develop initial loads for loads software that is especially useful if they are back calibrated from builds, although I have seen some of the smallest changes from a new design change the results dramatically and the testing and qualification start over. If you build a monolithic envelope structure you can sequence the build, windows and doors, lid, installed, to include one blower door test of the envelope. My mass design does this. You can get an idea of ventilation requirements and natural interior temp and humidity levels since all mass behaves different. You can see your internal temp drops, some have 65 degree inside temps with freezing outside temps just from mass effect and a small space heater is all that is needed. If you are stick building walls and internal load bearing structure, putting a drywall lid in last below an attic, some are doing several blower test along the way final when drywall is installed. I design to a build sequence that cuts my test and labor down. My drywall is integrated into my mass so I will not be waiting until it is in nor dealing with all the issues of sealing all it's interfaces. Design-to-build.