Ask the Carpenter: The pros and cons of tankless water heaters
Ask the Carpenter’s Rob Robillard talks energy-efficiency and offers advice on how to get paint off exterior brick.
Q. I’m thinking of replacing my gas water heater with a tankless on-demand one. I need enough hot water for two to three people. What are the pros and cons?
JIM GALLAGHER
A. A tankless on-demand heater can be a great solution to your residential hot water needs. The upfront cost is a bit pricey, but I think that in many cases the unit eventually pays for itself. I highly recommend them.
On-demand water heaters provide a continuous supply of hot water via energy-efficient and space-saving, self-contained high-powered burners. They do not store water. Standard water heaters do, and occasionally they have to reheat that stored water to keep it at a certain temperature. According to a 2013 report by the US Department of Energy, tankless water heaters can be 8 to 34 percent more energy efficient than water heaters with a storage tank, and depending on the amount of hot water your home uses daily, could save you at least $100 a year.
The cons? Well, the price and the fact that the limited flow rate means simultaneous, multiple uses of hot water can stretch a tankless water heater to its limit, the department said. For example, if you are running the dishwasher while someone is taking a shower. The solution is to install more than one tankless heater.
Have your plumber do a water consumption tally so you can size the unit based on your usage. The size and number of whole-house on-demand tankless water heaters you’ll need will largely be driven by the flow rate, and that is determined by the number and types of fixtures you may have running at one time.
Q. The brick first story on my house has paint stains that have run down from the second level. The worst seems to be below the window frames. How can I remove the stains without damaging the brick?
STU BASSLER
A. I always recommend hand washing before power-washing. Put on a pair of gloves and eye protection. Use a natural-bristle brush and a TSP (trisodium phosphate) cleaning solution. Wet the brick first, then apply the cleaning solution. Rinse and repeat until its gone.
Dear Rob
From dawnjohn44: I noticed in the Address article “Keep calm, winter on: Your guide to prepping your home for winter’’ (Oct. 14) that the Globe tells readers to check and change the batteries in their smoke and carbon monoxide detectors. I just became aware that many thermostats now have batteries, and if they need changing while you are away, the heat or air conditioning may not come on. This could be particularly problematic in the winter months. I don’t know whether many “snowbirds’’ are aware of this.
Rob: Thanks. That’s something folks going away for the winter, for even just the holidays, should consider.
Rob Robillard is a general contractor, carpenter, editor of AConcordCarpenter.com, and principal of a carpentry and renovation business. Send your questions to [email protected] or tweet them to @robertrobillard. Subscribe to our free real estate newsletter at pages.email.bostonglobe.com/AddressSignUp.
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