HVAC Calculators
Size your HVAC system with engineering-grade calculators
15 articles
Calculators
AC Tonnage Calculator
Here's the deal: both could be right, or both could be wrong. AC tonnage depends on far more than square footage alone. Your climate zone, insulation qu...
Air Changes Per Hour Calculator (ACH Formula)
Great question. Air changes per hour (ACH) tells you how many times the entire volume of air in a room is replaced in one hour. For a dental office, you...
Bathroom Exhaust Fan CFM Calculator
No — that's way undersized. A 120 sq ft master bath with a shower and tub needs at least 100 CFM using the fixture count method (50 CFM for the shower +...
Ceiling Fan Size Guide
It absolutely matters — and you're asking the right question. The wrong ceiling fan size either wastes energy spinning uselessly or fails to move enough...
CFM Calculator
We get this kind of question all the time. Figuring out the right CFM (Cubic Feet per Minute) for your HVAC system is one of the most fundamental — and ...
CFM Duct Sizing Chart & Calculator
Complete CFM duct sizing charts for rigid and flex duct, plus a calculator for supply and return duct sizing. ACCA Manual D methodology explained with worked examples.
Furnace Sizing Calculator
We hear this all the time. Furnace sizing is one of the most misunderstood parts of buying a new heating system, and getting it wrong costs you in comfo...
What Size Generator Do I Need
That moment of confusion is exactly why most people either buy a generator that's too small — and trip the overload breaker the first time they plug in ...
Heat Pump Sizing Calculator
Heat pumps are sized differently than furnaces or air conditioners. A furnace only heats. An AC only cools. A heat pump does both — and it has to satisf...
Heating BTU Calculator
Heating BTU Calculator --- How Many BTU To Heat Your Home
Heating Cost Per Square Foot Calculator
If your heating bill made you do a double-take, you're not alone. The average U.S. household spends $640 per winter on natural gas heating — but that nu...
How Many BTU Air Conditioner Do I Need
We get sizing questions like this every week. And the frustration is real — buy an AC that's too small and you're sweating through August; buy one that'...
Mini Split Sizing Calculator
We hear this constantly. Mini split sizing feels confusing because every manufacturer gives slightly different coverage ranges, and nobody explains the ...
What Size Tankless Water Heater Do I Need
If you've started shopping for a tankless water heater, you already know the sizing confusion is real. Unlike tank water heaters that are simply rated b...