Electric heat as secondary heat source only?

[Mech]

2018 IMC and IECC

Is there a code section anywhere that says electric resistance heat cannot be the primary source of heat? I am working on a big box store project and apparently they have run into this and the way around it is to install heat pumps when gas heat is not available. I mentioned it to one of the HVAC manufacturers and he indicated that the state of Washington and another one that I forgot do not allow electric heat as the primary heat source.

Is this anywhere in the IMC or IECC? I skimmed through the commercial building mechanical section of the IECC and found nothing. I do not know what section in the IMC to even begin looking for something like this.

Thanks.

 

[Yankee Chronicler]

I don't understand the question. The way around what?

If heat pumps are used for heating, the ground water thermal content is the primary source of heat, and any electric resistance heat is back-up for when the thermal can't generate enough heat in extreme conditions.

 

[Mech]

I don't understand the question. The way around what?

The way around using electric resistance heat as the primary heating source when gas is unavailable.

Apparently some states and jurisdictions will not allow electric resistance heat as the primary fuel source for HVAC systems. Gas (natural or propane) would be an alternative to electric as the primary heat source. A non-water heat pump extracts energy out of the exterior air and transfers it elsewhere, in this scenario to the interior air to raise its temperature. The heat pump operation is the primary source of heat and when the heat pump operation is inefficient, cannot generate the required amount of heat, or whatever other matrix is used to disable it, the electric resistance heat is used as the secondary source of heat.

 

[classicT]

I'm in WA.

WA takes the IECC, and then heavily amends it. So yes, in WA we have a code that would prohibit the use of natural gas or other combustion driven space and water heating. Electric resistance heating is also largely prohibited. Basically, either air source or ground source heat pumps are thereby mandated.

WA is however unique as well, given that the State Building Code Council (SBCC) who facilitates the development and adoption of the codes, has recently delayed the implementation of the 2021 codes due to concerns related to preemption by the Federal Energy Policy and Conservation Act (EPCA). Because of this, the SBCC re-entered rule making and is moving away from a direct prohibition on electric resistance and combustion driven space and water heating. So, although initially adopted, the rules will never be enforced. Rules to amend are currently in negotiation, with hearings set to happen next week.

WA 2021 Commercial Energy Code PRIOR TO EPCA AMENDMENTS
C403.1.4 Use of electric resistance and fossil fuel-fired HVAC heating equipment. HVAC heating energy shall not be provided by electric resistance or fossil fuel combustion appliances. For the purposes of this section, electric resistance HVAC heating appliances include, but are not limited to, electric baseboard, electric resistance fan coil and VAV electric resistance terminal reheat units and electric resistance boilers. For the purposes of this section, fossil fuel combustion HVAC heating appliances include, but are not limited to, appliances burning natural gas, heating oil, propane, or other fossil fuels.
Exceptions: {omitted for brevity}

 

[Mech]

Thanks classicT.

PA's version of the IECC does not have the additional code sub-section. It stops at C403.1.1.

 

[classicT]

Thanks classicT.

PA's version of the IECC does not have the additional code sub-section. It stops at C403.1.1.

Yes. WA has their own code that is very loosely based on the IECC. Significantly amended.

I was only intending to affirm what you had heard...

he indicated that the state of Washington and another one that I forgot do not allow electric heat as the primary heat source.

 

[Mech]

classicT: I appreciate you sharing. It affirmed and straightened out what I heard. I did not hear about not using gas or other combustibles and I did not know that extended to water heating as well.

I went back to the IECC to make sure PA's version did not amend section C403.1 so I can say I did my due diligence and have no knowledge on heating type restrictions.

 

[steveray]

WA is however unique as well, given that the State Building Code Council (SBCC) who facilitates the development and adoption of the codes, has recently delayed the implementation of the 2021 codes due to concerns related to preemption by the Federal Energy Policy and Conservation Act (EPCA).

At least it seems they recognized the error of their ways...

No prohibition in the State with the third highest electric rates in the country....Eversource loves the electric...

 

[classicT]

At least it seems they recognized the error of their ways...

No prohibition in the State with the third highest electric rates in the country....Eversource loves the electric...

Somewhat... the new amendments that go through a hearing next week will still in effect ban natural gas and electric resistance heating but does so via stacking on additional energy credits requirements. So, in theory, folks can still use natural gas or electric resistance, but have to offset the efficiency delta via additional measures that improve thermal envelope, PV generation, etc.

 

[steveray]

, PV generation, etc.

And of course...PV has nothing to do with "Energy Conservation" and is out of scope/ intent for the IECC but that is why we are appealing the 2024...And we will see how many lawsuits that brings...