â„ï¸ HVAC BTU Sizer

Don't freeze or sweat. Find the exact BTU requirement for your Mini-Split or Central AC.

Cooling / Heating Power Needed

BTUs per Hour

Recommended Mini-Split Size: 0 Tons

* Undersizing prevents cooling on hot days. Oversizing leads to rapid-cycling, preventing the system from properly dehumidifying the air.

📏 Thermodynamic Loads

Residential HVAC sizing is a complex calculation of heat gain, but can be estimated using reliable industry baselines for square footage.

      Required BTU = SqFt x 20 (base) + (Ceiling Additives)
    

The 'Ton' Constant: In North America, cooling capacity is often measured in tons. One "ton" of cooling is equal to 12,000 BTU per hour.
Ceiling Height Impacts: Standard 8ft ceilings allow for the 20 BTU/sqft rule. Every additional foot of ceiling height increases the volume of air that must be conditioned, requiring a higher static pressure and load.
Occupancy & Appliances: Kitchens and high-occupancy living rooms usually require an additional 2,000–4,000 BTUs to account for human body heat and cooktop heat gain.

💡 Expert Tip

Do not "Oversize" your system. A system that is too large for the space will cool the air so fast that it doesn't have time to actually dehumidify the room, leading to a "cold and clammy" feeling and potential mold issues in the ductwork.

💵 HVAC Sizing & Replacement Cost Guidelines (2026 Averages)

Understanding typical material and installation costs is key to planning a successful contracting project. Below are regional averages for cost planning.

House Size (Sq Ft)	Estimated AC Size	Required Furnace BTUs	Avg. Replacement Cost
1,000 - 1,200	1.5 - 2.0 Tons (18k - 24k BTU)	40,000 - 60,000 BTU	$4,500 - $6,500
1,500 - 1,800	2.5 - 3.0 Tons (30k - 36k BTU)	60,000 - 80,000 BTU	$5,800 - $8,200
2,000 - 2,500	3.5 - 4.0 Tons (42k - 48k BTU)	80,000 - 100,000 BTU	$7,500 - $11,000
3,000+	5.0 Tons (60k BTU or multi-zones)	120,000+ BTU	$12,000+

❓ Frequently Asked Questions (FAQ)

How do I translate AC BTU ratings into tonnage?

One ton of air conditioning is equivalent to 12,000 BTUs per hour of cooling capacity. For example, a 36,000 BTU cooling system is classified as a 3-ton unit, while a 24,000 BTU unit is a 2-ton system.

What happens if I install an oversized HVAC system?

An oversized HVAC unit cools the house too quickly, causing it to cycle on and off repeatedly (short-cycling). This increases energy consumption, accelerates wear and tear, and leaves excess humidity in the air, creating a damp indoor feel.