# Free BTU Calculator - AC Sizing for Arizona & California Homes

> Work out how many BTUs a room needs, adjusted for desert heat, ceiling height and sun exposure. Free AC sizing tool from Comfort Pros AZ and CA.

URL: https://www.comfortprosaz.com/tools/btu-calculator/

Free Tool - Calculator

# BTU Calculator

Estimate the cooling capacity a room actually needs, so you can sanity-check any system size you are quoted.

## Your details

Everything updates as you change it. Nothing is sent anywhere.

Room length(ft)

Room width(ft)

Ceiling height8 ft (standard)9 ft10 ft12 ft or vaulted

Where is the home?Phoenix metro / low desert AZInland Southern CaliforniaCoastal Los Angeles

Desert heat load runs about 25% above the national sizing rule of thumb.

Sun exposureShaded / north-facingPartial sunFull sun / west-facing

Room typeBedroomLiving roomKitchenOffice / study

People using the room1 person2 people3-4 people5+ people

Recommended cooling capacity

6,000 BTU

Room area

224 ft²

Roughly equivalent to

0.5 tons

### Single-zone mini split

A 9,000 BTU (0.75 ton) ductless head covers this comfortably. Common for a converted garage, casita or home office.

### Want this checked against your whole house?

Room-by-room math is a good sanity check. Sizing a system you are about to buy needs a load calculation on the entire home, and we will run one without sending a salesperson.

This is a room-level estimate using standard sizing rules plus a regional climate adjustment. It is not a Manual J load calculation and should not be used on its own to buy equipment. Real sizing depends on insulation, window glazing, duct condition, infiltration and orientation.

Related services

## What this usually leads to

AC Installation & Replacement

[/ac-installation/ →](/ac-installation/)

 

Ductless Mini Splits

[/ductless-mini-splits/ →](/ductless-mini-splits/)

 

AC Repair

[/ac-repair/ →](/ac-repair/)

More tools

## Other free tools on this site

Diagnostic

### HVAC Service Finder

Answer five questions and find out which HVAC service your situation actually calls for.

Open

[HVAC Service Finder →](/tools/hvac-service-finder/)

 

Running costs

### Energy Cost Estimator

Estimate what your air conditioner costs to run each month, and what a higher-efficiency system would cost instead.

Open

[Energy Cost Estimator →](/tools/energy-cost-estimator/)

 

Plumbing

### Water Usage Calculator

Estimate household water use, what it costs, and how much of it runs through your water heater.

Open

[Water Usage Calculator →](/tools/water-usage-calculator/)

 

Diagnostic

### Plumbing Service Finder

Describe the symptom and find out which plumbing service matches it.

Open

[Plumbing Service Finder →](/tools/plumbing-service-finder/)

![](/images/hero/candid-wide-photo-of-a-technician-shaking-hands-wi.webp)

Same-day appointments available

## Ready for an Honest Number?

Run a real load calculation online, or call the team in your state. Flat-rate pricing either way, and nobody shows up to sell you something bigger than you need.

Get Your TrueQuote

[https://quote.comfortprosaz.com →](https://quote.comfortprosaz.com)

 

(480) 435-2334

[tel:+14804352334 →](tel:+14804352334)

Flat-rate pricing, no upsells Parts and labor warranty Licensed in AZ and CA

California team: 

(818) 690-7951

[tel:+18186907951 →](tel:+18186907951)

 · Text us: 

(818) 489-2826

[sms:+18184892826 →](sms:+18184892826)