Heating and Air Guides: Mini Splits, Heaters, Dehumidifiers and Fans
Most heating and cooling mistakes are sizing mistakes. An oversized air conditioner short cycles and leaves the house damp, an undersized heater runs flat out and never catches up. Size by square footage, insulation and climate first.
These guides cover mini splits, garage and space heaters, dehumidifiers, humidifiers, whole-house fans and pool heat pumps, with what each costs to run.
11 heating and air guides
Pool Heat Pump Size and Cost to Run (With the Math)
Size a pool heat pump with surface area x temperature rise x 12, then price its running cost from COP and your rate, with above-ground and in-ground picks.
Top picks: Varpoolfaye 30,000 BTU 120V heat and cool pool heat pump, Varpoolfaye 65,000 BTU 220V inverter pool heat pump with WiFi, Hayward HeatPro W3HP31005T 100,000 BTU heat and cool pool heat pump
Updated Oct 13, 2026
Best Dehumidifier by Room Size: 35 Pint, 50 Pint and Crawl Space
Dehumidifiers matched to room size and dampness: 35 pint for bedrooms, 50 pint for basements, crawl space units for cold spaces, and what each costs to run.
Top picks: Midea Cube 35 Pint Dehumidifier, Midea Cube 50 Pint Dehumidifier, AlorAir Sentinel HD55S 120 PPD Crawlspace Dehumidifier
Updated Oct 13, 2026
Best Garage Heater: 120V, 240V, Propane or Natural Gas by Garage Size
Garage heaters matched to size and insulation: 120V spot heat, 240V electric, vent-free and vented propane or natural gas, cost per hour and safety.
Top picks: Comfort Zone CZ220BK 5,000 W Ceiling Mount Garage Heater, Comfort Zone CZ260ER 10,000 W Ceiling Garage Heater with Remote, Mr. Heater Big Maxx 80,000 BTU Vented Garage Unit Heater
Updated Oct 28, 2026
Best DIY Mini Split: Pre-Charged vs Pro Install, Sized by Room and Climate
Mini-splits matched by room size and climate: pre-charged DIY vs pro install, 115V vs 230V, hyper-heat for cold winters, multi-zone, and yearly cost to run.
Top picks: MRCOOL DIY Select 12,000 BTU 115V Mini-Split Heat Pump, Senville LETO 9,000 BTU 115V Mini-Split Heat Pump, Senville AURA 9,000 BTU Hyper-Heat Mini-Split
Updated Oct 28, 2026
Best Whole House Fan by Home Size: CFM, Attic Venting and Savings vs AC
Whole house fans matched to your square footage at 15 to 20 air changes an hour, with the attic vent area each needs, quiet ducted vs louvered, and AC savings.
Top picks: QuietCool Classic CL-4700 RF Whole House Fan, QuietCool Energy Saver ES-4700 RF Whole House Fan, QuietCool Classic CL-3100 RF Whole House Fan
Updated Oct 28, 2026
Best Crawl Space Dehumidifier: Sizing, Pumps and Encapsulation
Crawl space dehumidifiers sized by square feet, AHAM vs saturation pints explained, pump or gravity drain, and what one costs to run in a sealed crawl space.
Top picks: AlorAir Sentinel HD55S 120 PPD Crawlspace Dehumidifier, Argendon Sandidry 55C 120 PPD Crawl Space Dehumidifier with Pump, AlorAir Helios D35 Energy Star Crawlspace Dehumidifier (70 PPD at saturation)
Updated Oct 28, 2026
Best Humidifier for a Bedroom or Large Room, Sized by Square Feet
Room humidifiers matched to square feet: evaporative vs ultrasonic vs warm mist, gallons per day, white dust from hard water, and the yearly cost to run.
Top picks: Levoit Superior Studio Evaporative Humidifier (4.5 L), Levoit NeoClassic 450 Ultrasonic Cool Mist Humidifier (4.2 L), Levoit LV600S Smart Warm and Cool Mist Humidifier (6 L)
Updated Oct 28, 2026
Best Whole-House Humidifier by Home Size: Bypass, Fan-Powered or Steam
Whole-house furnace humidifiers sized by square feet and gallons per day: bypass, fan-powered and steam units from AprilAire and Honeywell, plus HVAC UV lights.
Top picks: AprilAire 500 Automatic Bypass Humidifier, AprilAire 700 Automatic Fan-Powered Humidifier, AprilAire 800 Whole-House Steam Humidifier
Updated Oct 13, 2026
Best Window Air Conditioner by Room Size (and Cost to Run)
Window ACs matched to room size with the ENERGY STAR chart, 5,000 to 23,500 BTU, with what each costs per hour and per month to run.
Top picks: Midea U-Shaped 8,000 BTU Inverter Window AC, Frigidaire 10,000 BTU Smart Inverter Window AC, LG 12,000 BTU Dual Inverter Smart Window AC
Updated Oct 13, 2026
Best Air Purifier by Room Size (and What Each Costs a Year)
Air purifiers matched to room size by AHAM smoke CADR, with the yearly cost of power and filters. From a budget bedroom unit to a 435 cfm purifier for open plans.
Top picks: Levoit Core 300-P True HEPA Air Purifier, Winix 5520 4-Stage True HEPA Air Purifier, Blueair Blue Pure 211i Max Air Purifier
Updated Oct 13, 2026
Best Basement Dehumidifier and What It Costs to Run
Basement and crawl space dehumidifiers sized by square feet, with running cost: about $19 a month at the US average rate for a typical unit.
Top picks: AlorAir Sentinel HD55S (55 pints AHAM, Energy Star), AlorAir Sentinel HS35 (70 PPD, Energy Star), AlorAir Sentinel HD35P (built-in pump)
Updated Oct 28, 2026