Energy Calculation For Residential Addition 3

[aswierski]

I'm doing a 14' x 38' addition to an existing residence and the client wants me to do energy calculations. Does anyone have any reference material on this? I'm not sure where to start as I've never done energy calcs before, so any info on this would be greatly appreciated.

 

[dgkhan]

you cannot do it. A mechanical engineer doest it. I have some one who can do it for you. Give me your contact.

 

[aswierski]

Why do you say I cannot do it? I'm not looking for someone to do this for me, I would like to learn to do it for myself in case a client wants the same thing in the future.

 

[dgkhan]

I am sorry If I hurt you in any way. As a str engr it will take you a lot before you can create this, different trade report, own your own.
For example can you provide geo techinical report if client asks?

 

[aswierski]

No worries... This is a smaller job, so I'd rather not have to sub anyone out...

 

[Ron]

While I'm sure you could handle the math for the energy calculations, such work is under the purview of mechanical engineers. Chances are you could do it and get it through the building department; however, your state law likely prohibits this action, assuming you are not a licensed mechanical engineer.

 

[MaddEngineer]

The Department of Energy provides free software that will do a detailed analysis to determine required insulation in order to comply with the Model Energy Code (MEC), International Energy Conservation Code (IECC) and your Local State Code. Or you can use the prescriptive method found in your states energy conservation code based on the type of construction and area of window and door openings. Basically the calculations are to determine the the R-Values for the roof and wall insulation, it is not really that complicated. Architects typically just run the DOE program and paste the output into the drawings or you can use the prescriptive methods, it shouldn't take you more than 30mins or so, even less once you know what you are doing. It's been a few years since I have done one. Hear is the link to the DOE:

 

[FSS]

The HVAC sub should do them, and they are set up already with the programs, etc. You don't want to mess with this. Not worth the trouble.

 

[CFSEng]

For a 532 sq ft addition it's probably not worth the trouble to hire an HVAC person. I did this for my addition to my house and spent around 30 minutes. Of course my calcs were for my own house, you would have an increased liability providing the calc for someone else. Just make sure your compensation matches your liability exposure and you should be all set, otherwise let them hire someone else to do.

 

[aswierski]

Thanks gang. I went to look at the residence, and the need for this addition stems from the owner finding mold spores in his house. So now insurance companies are involved, the health department is involved, and the town is breathing down their necks. I guess I should have visited the site before I agreed to take this project on. The owner never mentioned any of this until I had already agreed to do it. I haven't signed anything, only verbally committed. I'm in my mid-twenties so my experience in this area is lacking. Do you guys have any recommendations on how I can get out of this project?

 

[SteelPE]

Doing the energy calculation is easy. As MaddEngineer states, all you need is the DOE computer program and the information about the addition (window size/U value, wall area/R value, ceiling area/R value, door area/U value, heating system/efficiency….). Plug the information into the program and it tells you whether or not you are in compliance.

I would say the sooner the better if you are looking to get out. Be honest with the client and tell them the job wasn’t quite what you thought it was and you are a little over your head.

 

[RareBugTX]

Dear Aswiersky:

For that job size, and if you want to learn, you can do it. I do not want to get into legal lingo here cause I do not want to.

The Department of Energy has two versions of a free software called Rescheck, you can google it. An option for Commercial Structures is called Comcheck. You can download it for free at the DOE's website. Its use is very intuitive so you as an engineer should have no problem in figuring it out.

I have learned to do many things that many told me not to try, and feel comfortable now doing them as long as the public safety and welfare are not in jeopardy. Just be conservative.Sometimes is useful to be practical.Use your judgement.

Make sure that you check the partition types, insulation values for wall ceiling and floor accordingly and the heat loss and gain assumptions that make sense to the are where the house is located.

By the way, you will see that the DOE assumes that even contractors can run this software and they accept the output reports prepared by them as long as the assumptions are logical and done with diligence.

 

[aswierski]

RareBug,

I've downloaded ResCheck, and it is very easy to use. I had no problem figuring it out. It took me about 30 minutes to input all my values. The only question I have left regarding the energy calcs is regarding doors and windows. I do not know what type of windows/door the owner will be purchasing (neither does he yet), so I'm not sure what U-value I should be using. Any thoughts on a conservative number?

 

[MaddEngineer]

Here is a link to Andersen Windows NFRC/Energy Star Information. It gives the upper limit U-Values for there product lines per NFRC (National Fenestration Rating Council)Certification. I think you can use these upper limit values since Andersen is the most available standard window. You can then specify Andersen 200 Series or equal with the required upper limit on the U-Value. Andersen also makes patio doors and skylights. For the exterior doors you can check out Stanley Doors.

 

[MaddEngineer]

Here is a link to Jeld-Wen windows and doors performance data... They manufacture exterior entry doors and windows. They are also readily available at Home Depot, etc. Basically the steel door is the basic model, then fiber-glass, then wood... The price tends to go up as you change materials.

 

[cvg]

no signed contract, no worries. if their is any chance of future legal action, than run like the wind. you do not want an attorney asking you on the stand if you have any experience as a HVAC engineer and your answer is "gee no, but I downloaded a free program and taught myself how to do it..."

 

[MarkVR]

Not sure about where you are, but in Florida there is a 'short' form for small additions. You might try that route where you live.

Also worthy of note, in Florida you are not required to have A/C, only have to show that the place can be heated adequately. That is something many jurisdictions to not know or want you to know. "why?" you ask, well, they want that permit fee.

You do not have to be a mechanical engineer to fill out the energy forms in Florida. I usually get the home owner to sign the forms anyway.