There has been renewed interest in this conversation
Let's keep it going 2018 / 2019 style!
Hi Brett, since the archive discussion you linked is locked to new posts, I think the best way to continue the conversation would be cite something specific from that thread here, to stimulate additional discussion.
To answer the question posed in your headline, there's no inherent impact of ductless on HERS index beyond the equipment's efficiency ratings. Nor should there be.
In calculating the HERS Index, the software considers equipment SEER/HSPF ratings and duct losses, if any. So a 17 SEER / 9 HSPF conventional system with ducts inside conditioned space would be considered equivalent to a ductless mini with the same efficiency ratings.
Sounds fair but will anyone see it? Maybe this can get promoted?
In our webinar about ducted air source heat pumps featured now on youtube here Mitsu claimed that ductless usually boost the HERS index rating over ducted systems. They went on to explain it further.
So here is my question
1) Has anyone done any studies to prove that?
2) As we try to get more people who have less financial means to zero energy, is going ductless one of the ways to do that by 1) Saving money in upfront costs and 2) Boost energy reductions to lessen the amount of solar needed to get to zero energy capable?
Also, reading your message David, I think there would be disagreement.
Choosing the Right System for Your Home.
Depending on what kind of home you have, your options for cooling systems may be limited. For example, installing ductwork in a home built without it is much more difficult than installing a mini-split system.
Though the two have a few energy-efficiency differences, if you’re concerned with the environment or want to save on energy bills, you have options. Remember that both new central air and mini-split systems are far more energy-efficient than window air-conditioning units.
Thanks Franco but how does that impact HERS?