Energy analyst is telling me that my ADU has 28% glazing so needs Hers for the Minisplit and also that there has to be heads in each habitable room, (doesn't include bathroom.) I hate these rules. Cooler bedrooms are fine and heat rises. (In this case bedroom is above) Minisplits are too ugly to have them on every wall. Sizing also seems overkill. Hard to keep tiny houses to 20% glazing so all these requirements add up to way over complicate things!
Sarah Deeds posted in HVAC, DHW & Plumbing
2 months ago
Public
You are correct that it's overkill to have a head in each room. It usually leads to drastic oversizing and lower energy and comfort performance. I think the HERS requirement (adequate air flow to each room) is triggered by choosing a variable capacity heat pump (vchp) as the heating system in the energy model. The vchp option typically improves compliance margins, but comes with additional requirements. Switching the system in the energy model to 'ductless minisplit heat pump' should remove that air flow requirement, allowing for a single, central ductless unit. It will likely lead to a lower compliance margin, but it might not matter if it's all-electric with a heat pump water heater.
Sarah Deeds Deeds Design , what is spec'd for DHW? And what is size of ADU? With only 28% glazing (super low for an ADU, since that % is based on floor area) I'm surprised you are having trouble passing... makes me wonder if you're taking advantage of the elec resistance tankless "exemption"?
We are sharing the main house HWH. Not having trouble passing exactly
I added the requirements last time around to my original post. He said the windows also had to be higher standard, but I think the numbers were easy to meet.
It is currently a gas on demand...so perhaps that is a ding.
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