Yes, the sum of the credits without limitation would be $2,300 ($600+$500+$1,200).
Next, there is a maximum credit per year. According to the IRS, the maximum credit you can claim each year is:
- "$1,200 for energy efficient property costs and certain energy efficient home improvements, with limits on exterior doors ($250 per door and $500 total), exterior windows and skylights ($600) and home energy audits ($150)
- $2,000 per year for qualified heat pumps, water heaters, biomass stoves or biomass boilers"
Windows, doors, air conditioning, and furnaces are energy efficient property costs and certain energy efficient home improvements subject to a total maximum of $1,200.
