Homeowners
Plain-language cost guides for homeowners: repair versus replace, running costs by state, safety, and how to read an HVAC contractor’s quote.
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Cold Climate Heat Pump: The ENERGY STAR Criteria and What 5F Ratings Mean
The Cold Climate designation is two measured numbers at 5F, not a marketing phrase. What ENERGY STAR Version 6.2 requires, what DOE’s Challenge proved, and how to check…
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Air Conditioner Decibel Levels: What the Sound Ratings Actually Mean
Air conditioner decibel levels are laboratory ratings on a logarithmic scale. Here is what sound power, sound pressure and sones each mean, and which noise rule actually binds…
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Furnace Flame Color: What Blue, Yellow and Orange Actually Mean
A blue furnace flame means the burner is getting roughly its design air. A persistent yellow flame means it is not. Neither appearance measures carbon monoxide, draft or…
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HVAC Permit Requirements: When You Need One and What Happens If You Skip It
Most jurisdictions treat an HVAC equipment replacement as permitted work. Here is what the permit buys, which jurisdictions exempt in-kind swaps, and what unpermitted work costs at resale.
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Water Heater Temperature Setting: 120 vs 140 Degrees, Settled With Federal Data
DOE and CPSC both say 120 degrees Fahrenheit. CDC says store above 140 to control Legionella. Both are right, and a mixing valve is why.
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CFM Per Ton: The Airflow Rule Behind Every AC Diagnosis
A ton is 12,000 Btu/h, and the federal test procedure assumes 400 scfm per 12,000 Btu/h when nothing else is certified. What that means for freezing coils, humidity…
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How Many Watts Does an Air Conditioner Use? Draw by Equipment Class
Running watts and amps for eight classes of home HVAC equipment, derived from ENERGY STAR certified ratings, 10 CFR 430.32 and EIA data, with the arithmetic shown.
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Gas Fireplace Venting, Efficiency and Safety: Direct Vent, B-Vent and Vent-Free
Direct vent, B-vent and vent-free gas fireplaces differ sharply in efficiency and indoor air. What the FE rating means, why no federal standard applies, what a standing pilot…
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Pool Heater Types Compared: Gas, Heat Pump and Solar on the Federal Numbers
How gas, heat pump and solar pool heaters work, the 10 CFR 430.32 efficiency standard that changes on May 30, 2028, DOE sizing rules, and season running costs…
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Home Energy Audit: What the Blower Door Measures and How It Changes HVAC Choices
What a professional home energy audit measures, what CFM50 and ACH50 mean against the IECC limits, who can issue a DOE Home Energy Score, why the 25C audit…