New boiler? Minis? What next?
Daughter and husband recently moved to Cape Cod on Long Island sound, 1150 sf, poorly insulated/sealed. Heated by 60? year-old boiler, estimated 50% efficiency by furnace maintenance. They like the radiant warmth, but are using 100 gallons per month or more at 68 when they’re home and 62 when not. Electric hot water w/leased 80 gal tank. Cooling has been with window units. Good shade to SW and W. Natural gas not available and opposed to idea of going to propane.
They’ve been quoted $7K to replace boiler with 85% efficiency, and have also gotten a quote of $18K to do Carrier minisplit system that would be aimed at keeping them comfortable to 0 degrees F and keeping the old boiler as backup.
Assuming energy audit and sealing/insulating done per recommendations, what should they consider going forward, both from the comfort standpoint and the responsible use of resources? The minisplit option seems pricey and keeps the old boiler online. The boiler update is affordable, but is a half-measure and doesn’t provide any cooling. Ideas?
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If it were my call, I'd opt for a new boiler, as nothing beats the comfort of hot water baseboard heat. I would also look for a less costly mini-split to provide cooling, and to help offset some of the fuel oil demand.
Was that 7k estimate from the same company that said the boiler was only running at 50% ? It may help to shop around or get another check up by another technician just to make sure. A good cleaning, burner adjustment and nozzle change would be the first thing I would do. You may be able to change out the nozzle with a smaller one to use less gallons per hour and still get the same performance with less heat going up the flue. The boiler itself absorbs the heat it needs and once it is at temp it won't absorb as much and that is where you start to lose heat up the flue, so lowering GPH should still maintain internal boiler temps. I would estimate an oil fired boiler for that size house would be 3k at the most to purchase. If all other aspects of the system are okay, pumps, controls etc., it should be an easy swap out. If they are talking you into changing all these things, I would find another installer who is willing to keep all the old components to save you some money. If you can make it through this winter, installing it in the summer may save you some money also since it is not an emergency swap out.