How do I model a Mini-Split, Multi-Split or VRF System for Residential Compliance?

For conventional ductless heat pumps (mini-split, multi-split VRF systems) the CEC Compliance Manager simulates these as a system equivalent to the standard minimum efficiency split system A/C with a fully ducted system in the attic, thus affording no credit

When inputting these systems, each OUTDOOR unit should be input at the System level of the Tree as its own System, with a corresponding Zone, thus allowing for the necessary HERS field verification.  Do not worry about the details of the indoor units.  You have the option to take compliance credit for these systems as a VCHP (Variable Capacity Heat Pump) system.  In the case of a VCHP, which requires an indoor unit installed in each habitable room over 150 sqft, we offer the checkbox at the System level of the Building Tree, Residential tab.  Note however that when using this feature, changing the efficiency will not impact the VCHP credit.

You will see the VCHP verification criteria on the CF1R under HERS Feature Summary, and a new section “Variable capacity heat pump compliance option – HERS Verification” on the CF1R, including a comprehensive list of HERS measures for verification.  Our sample file Res Mini-split demonstrates this feature.

Appendix B of the VCHP staff report is entitled VCHP Compliance Credit—Eligibility Verification Protocols. This document describes the criteria to be met and is available from the newly established CEC website dedicated to VCHP.

Categories: 4. Single Family Title 24
Tags: , ,

← Frequently Asked Questions

Comments are closed