Home Improvement

Ask the Remodeler: Should you add antifreeze to your HVAC system?

Plus, issues with a shower door seal. Send your home improvement questions to [email protected].

A frozen pipe with ice hanging off of it.
Temperatures are plummeting. How to avoid freezing pipes in your vacation home. Adobe Stock

Q. We have a 1908 vacation home in Rhode Island with forced hot water heat. Around when we purchased it back in the ‘90s, I asked an HVAC contractor whether we could put antifreeze into the system, and he said no, that the acidity would eat through our old (copper?) metal pipes and cause pinhole or worse. I was told recently that heating system antifreeze has buffers, so this is no longer a problem as long as we keep up with yearly maintenance. The current hot water heater is an on-demand “tankless” system heated by the same boiler. I would assume that the two systems are completely separate and that there is no chance we could drink or bathe in antifreeze-tainted water.


Should we add the antifreeze? It’s been a temptation to rip the system out and replace it entirely with mini splits, so that we have fewer pipes to worry about bursting when the power goes out (although I’ve been told that we should have a backup heating system if we get mini splits).


A. Our plumber uses antifreeze in certain systems that may be susceptible to freezing. A vacation home is a good example of that. Perhaps older antifreezes could corrode pipes; modern ones should not. You need a different type of antifreeze for aluminum heat exchangers, so be sure to have this done by a qualified plumber. The water in your heating system is totally independent of the potable water used for drinking and household use.

If the house is unoccupied for the winter months, you may want to consider draining both the heating and household water lines until spring. That is always the safest bet. Otherwise, having your plumber add antifreeze into the system is a good option.

Q. We have a frameless glass shower door. The seals on each side of the door are beginning to separate from the glass. Is there an adhesive that can be used for this application? We tried Super Glue, but that did not work. Or is it better to just replace each of the seals?



A. I recommend calling a local glass company to reinstall the right seal with the proper type of adhesive.

Mark Philben is the project development manager at Charlie Allen Renovations in Cambridge. Send your questions to [email protected]. Questions are subject to editing.


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