Walk into any Medford basement and read the boiler’s nameplate — then understand that the number is probably wrong for the house. Most of these units were sized decades ago for drafty envelopes: single-pane windows, uninsulated walls, air leaking everywhere. The houses have since gained insulation, better windows, and sealed gaps — but the boiler stayed the same size. Replacing like-for-like repeats a 30-year-old error, and an oversized boiler short-cycles: firing in bursts, never reaching steady efficiency, wearing components faster.
Proper sizing means a heat-loss calculation for the house as it stands today — windows, insulation levels, air sealing, and a full inventory of the radiation (radiators or baseboard) already installed. Most Medford replacements downsize meaningfully once the math is done, which improves efficiency, lengthens run cycles, and often costs less than the oversized quote. Demand the calculation by name, plus near-boiler repiping, outdoor reset controls, and startup tuning verified with combustion instruments — the package that makes the new unit actually deliver its rated efficiency.
