Learning heat loss calcs - looking for infiltration factors

Macro

So I'm learning about heat loss calculations and boiler sizing etc. but I would like to be able to do that calculations myself manually before relying on a program or online calculator. I am finding it impossible to find the infiltration factor multipliers anywhere though. Can someone direct me to them? I don't mind if I have to pay for a download or book but I can't find it. I'm an ICI plumber but trying to expand my resi knowledge and skills to grow my own business. Thanks!

Alan (California Radiant) Forbes

This is how we used to do heat loss calculations in the "old days":
https://heatinghelp.com/assets/documents/110.pdf
Thanks to Erin, Dan and HeatingHelp for keeping this in their archives.

GW

Infiltration, that’s the wild west, unless you have a blower door. This is a basic fundamental, the taller the structure, the more infiltration. The older the structure, the more infiltration. It’s likely why the old-timers put these huge radiators in the front entry/hallway.

Macro

Alan (California Radiant) Forbes said:

This is how we used to do heat loss calculations in the "old days":
https://heatinghelp.com/assets/documents/110.pdf
Thanks to Erin, Dan and HeatingHelp for keeping this in their archives.

Thanks! There's a lot of old and roughly built homes where I am that I think this would be useful for. Is there any other resources you can suggest for learning about this stuff? I see reference to "Manual J" sometimes but I don't know what that is!

STEVEusaPA

Alan (California Radiant) Forbes said:

This is how we used to do heat loss calculations in the "old days":
https://heatinghelp.com/assets/documents/110.pdf
Thanks to Erin, Dan and HeatingHelp for keeping this in their archives.

That one's too old, doesn't account for global warming. Neither does mine from the 80's.

Macro

Do you have a recommendation for where I can find something updated? Or even wheat to search for?

Jamie Hall

Macro said:

Do you have a recommendation for where I can find something updated? Or even wheat to search for?

I think at @STEVEusaPA was joking -- the basic concepts haven't changed a bit, global warming or no. The only thing really lacking -- and easily accounted for -- is better insulation in more recently built or upgraded structures.

EBEBRATT-Ed

@Macro

Doing a few calculations manually is a good idea. Anyone can plug in a program and get results , but they won't know right from wrong.

Doing a few manually will give you an understanding of how it works.

Slant Finn has an app you can download that people use that is pretty good.

Zman

Infiltration factor is always a bit of SWAG. The height of the building, location of the leaks, wind exposure and mechanical fans all play a factor.

A blower door test eliminates many variables. comparing past utility bills to heating degree days is also a good trick.

I like this article.

Macro

EBEBRATT-Ed said:

@Macro

Doing a few calculations manually is a good idea. Anyone can plug in a program and get results , but they won't know right from wrong.

Doing a few manually will give you an understanding of how it works.

Slant Finn has an app you can download that people use that is pretty good.

I was having a look through it and it seems pretty comprehensive, almost too much for me! I'm not familiar with all the different variables you can choose from (wall types mostly) so I need to dig into it a little more.

mattmia2

Some of the inputs to the heat loss are always a best guess. The r-value of windows and wall and ceiling assemblies are also a best guess.

RNB716

I just went through this myself.... As a DIY project mind you. Without learning too much, lol, I found this to be of help.

best of luck with your project.

Dave H_2

Take a look here, we went into detail on heatloss during the first few sessions of Taco After Dark, Summer School
https://www.youtube.com/watch?v=52VCNqchLGo&list=PLsbNhUC4lCm_2aouRyJRpKXFBNHmW5nN_&index=14

Dave H.