Replies

1. GBA Editor
   Martin Holladay | Mar 15, 2013 07:59am | #1

   Stephen,
   Are you sure that heating and cooling equipment needs to be approved by the California Energy Commission before it can be legally installed? I find that hard to believe.

   I've never heard of any legal problems in California related to the installation of ductless minisplit units.

2. 
   Steve95065 | Mar 18, 2013 07:29pm | #2

   The California Energy Code (usually called Title 24) , like most other energy codes, compares your building with a "Model" building of the same size and you need to prove it is at least as efficient as the model home. Electric resistance heating is almost completely forbidden unless there is no alternative. Heat pumps are allowed but right in the introduction to the chapter it says "If you do plan to use it, there are some pretty big tradeoffs and you must use a unit "Approved" by the CEC.

   Steve

3. GBA Editor
   Martin Holladay | Mar 19, 2013 07:49am | #3

   Stephen,
   That's news to me. Do any other GBA readers have more information in this issue? Is there a published list of CEC-approved ductless miniplits?

4. Expert Member
   Dana Dorsett | Mar 19, 2013 04:55pm | #4

   IIRC under CA Title 24 2008 (currently in effect) heat pumps must have a minimum HSPF of 7.7 to be used for heating in CA under Title 24, and an SEER of 13 or greater, hurdles very easy to clear for most mini-splits. Beyond that, SFAIK there are no special certification & labeling requirements for installing them- there is no "CEC approved equipment list", just a minimum efficiency spec.

   Somewhat dicier, mechanical systems may not be oversized by more than 15% for the load(s) per a Manual-J calculation, which may be impossible to meet for small-house small-load situations, even with a 3/4ton mini-split. There bits in the code for HVAC systems regarding ducts that don't apply with mini-split, nor does the code sufficiently address the fact that most high efficiency mini-splits are fully modulating systems with more than 3:1 turn down, and will actually run at somewhat higher average efficiency when oversized for the peak loads by about 25%.

   Then there's the refrigerant charge inspection verication rules that can't always be strictly complied with. Mini-split issues are currently under active investigation for purposes of updating the CEC for 2013 (which becomes effective January 1 2014) since much of the verbiage in current code presumes ducted split systems, with refrigerant charge verification methods commonly used in split systems that simply can't be followed in all ductless cases due to real structural differences eg:

   http://www.energy.ca.gov/title24/2013standards/prerulemaking/documents/current/Reports/Residential/HVAC/20110927Temple_MiniSplit_Investigation_acptchng.pdf

   And see section on page 51 (.pdf pagination) here:

   http://www.energy.ca.gov/title24/2013standards/rulemaking/documents/final_rulemaking_documents/23_March_13_Hearing_Residential.pdf

   But SFAIK that has never stopped mini-splits from being installed in CA, as long as they meet the 7.7HSPF/SEER13 minimums, and are often a listed feature in deep energy retrofits presented as exemplary projects, eg:

   https://www.smud.org/en/residential/save-energy/success-stories/documents/Case-Study-Jean-Ave.pdf

   Title 24 2008 in fact DID make accommodating specifications for PTHP/PTAC units, but for somehow mini-splits escaped the regulatory radar when that was being drafted. See:

   http://www.energy.ca.gov/2008publications/CEC-400-2008-016/rev1_chapters/RCM_Chapter_4_HVAC.pdf

   Bottom line, aside from a potential oversizing specification issue for such a tiny/low-load space, almost ALL mini-splits would exceed the basic raw efficiency requirements under the CEC with margin. There is no special certification or labeling step required for approval- just published & verifiable HSPF and SEER numbers that meet the spec. With literally hundreds of mini-split installers in the state, you'd probably have to go way out of your way to find a mini-split for sale in CA that wouldn't pass muster with the CEC.

5. GBA Editor
   Martin Holladay | Mar 20, 2013 09:07am | #5

   Dana,
   Thanks very much for the helpful information.