NOTE: NYSERDA users follow the instructions on this article instead.

On the input screen fill out the data for the existing attic:

After the first model, go to the refine screen and edit the attic recommendation. Change the improved sqft and insulation to zero (not blank).

Move the Vault recommendation from declined to recommend, then click on the Add Vault button.

Edit the improved vault fields, and entering zero for the base values. You can use our roof pitch conversion chart for to help calculate the sq ft of the slopes.

Vault and Slope Calculations

In addition, you should also add additional wall square footage to accomodate the new gable end that you have created. If you are insulating the gable walls differently than the rest of the home's walls, you should create a 2nd wall system and set the base wall sqft to 0 and the improved wall sqft to the total sqft of the gabled ends.

After modeling the job again, you will see that you have a positive savings in the attic section, and a negative savings in the vault section.

The attic is showing a positive savings because the attic floor has been brought into the conditioned space. The vault is showing a negative savings because this is a new space that was not previously modeled or insulated. The overall savings is the net between the two. In this case, the savings would be $45.

It would be important to have both measures as recommended, so you would get the true net savings. You could edit the titles if it would be easier for the homeowner to understand.

Here's another example of a more complicated conversion. In this instance we have a cape cod where we're insulating the vaulted areas behind a knee wall. The house is 20 feet wide by 40 feet long and has 1200 sqft of conditioned space.

Here is a view of the original (base) home. The blue color represents the building envelope.

Here is the converted (improved) space:

And here's what the various Now and Goal sections look like for the different surface areas in the home: