By Mark Adams, Chair, Green Homes and Buildings Group
The Marblehead Old and Historic Districts Commission (OHDC) recently updated their guidelines to allow consideration of heat pump line sets that are visible from a public way. Previously, this was strictly prohibited. Heat pumps, since they provide highly efficient electrified heating, are one of the best ways for homeowners to reduce their monthly energy bills and carbon output. More on heat pumps can be found in this blog.
The previous guidelines were seriously impacting the ability of Marblehead to reach its goal of achieving net zero in carbon output by 2040 because far too many homeowners in Old Town were finding it difficult to impossible to covert to electrified heating. This blog will provide tips on how Old Town homeowners can install heat pumps for electrified heating and stay within the new guidelines.
Heat pump systems have outdoor condensers that extract heat from the atmosphere. By the OHDC guidelines, condensers must be shielded from public view. Condensers that can’t be located in the rear of the house can be shield by shrubbery, fencing or a lattice box like the one shown here.
Lattice or spaced slats, rather than solid walls, should be used to allow for proper air flow. Fortunately, shielding the condenser usually isn’t too difficult to do.
External Line Sets
Many homeowners and their installers prefer to install ductless minisplit systems with heat pumps as this is frequently the most cost-effective solution. The installation will need to include line sets that carry the refrigerants from the condenser to the minisplit units within the rooms that are to be heated and cooled. If placed on exterior walls that are visible from the street, the OHDC commissioners will want to see the following in an application:
The lines must be covered, and the commissioners strongly prefer metal pipes or wood (see photo below) rather than standard PCV covers.
The covers should be painted to match the color of the exterior walls.
The line sets must be fully vertical. No horizontal extensions will be allowed.
The line sets should not be placed on the front or street facing exterior wall.
If possible, the line sets should be fully or partially obscured by another feature like a chimney.
Internal Line Sets
If possible, consider having the refrigerant line sets to the minisplits routed through existing conduits within the walls or route the line sets within the walls if they aren’t already insulated. Another possibility is to place the line sets in closets or in room corners that can be covered with wall board.
Internal line sets do not require approval of the OHDC and can be installed at the homeowner’s discretion.
Air to Water
If the home is currently heated by an oil or natural gas boiler, the exiting hot water distribution pipes and the radiators or baseboard heaters may be capable of being connected to an air-to-water heat pump. These installations come with the least disruption to the house because the existing water lines and heating elements are maintained. However, air to water heating is typically more expensive than ductless minisplit heat pumps. And fewer contactors are qualified to install them. Typically, installers who will bid on air source heat pumps with minisplits do not also install air-to-water heat pumps.
A great way to find contractors is to sign up for an energy audit and discuss your heating system needs. Customers of National Grid who use natural gas to heat their homes qualify for the Mass Save program and can schedule an audit by calling 866-527-7283. All Marblehead residents are eligible for the Next Zero program and their energy audits can be scheduled by calling 888-333-7525. Both audit programs will cover suggested insulation upgrades that will further reduce the energy needed to heat and cool a home. If eligible for both Mass Save and Next Zero, then Mass Save is the recommended option because the program offers higher rebates for efficiency upgrades.
Serving on the OHDC
While the new guidelines open the possibility of easier approvals of heat pump systems in Old Town, how they are applied to individual applications is still at the discretion of the OHDC board members. If you are a resident within the Historic Districts and are sustainably minded, then please consider applying for an OHDC board position with the town’s Select Board.