How many tons is 12,000 BTU/hr?

12,000 BTU/hr equals exactly 1 ton of refrigeration. This is the single-zone benchmark for residential AC.

How many tons is 24,000 BTU/hr?

24,000 BTU/hr equals 2 tons — a common size for small homes or two-bedroom apartments.

How many tons is 36,000 BTU/hr?

36,000 BTU/hr equals 3 tons — the typical sweet spot for a 1,500–2,000 sq ft moderate-climate home.

How many tons is 60,000 BTU/hr?

60,000 BTU/hr equals 5 tons — the largest standard residential size and the entry point to light commercial cooling.

Can I have a 1.75-ton AC?

Manufacturers don't build fractional sizes below half-ton steps. Loads between 1.5 and 2 tons are typically met by oversizing to 2 tons or using variable-speed equipment that can modulate down.

Is 1 ton AC enough for a bedroom?

Usually yes. A 1-ton (12,000 BTU/hr) unit handles roughly 400-600 sq ft in moderate climates. Hot, sunny, or poorly insulated rooms may need more.

Does heating use the same ton-to-BTU conversion?

Yes. Heat pumps move heat in both directions; their nameplate ton rating refers to the cooling-mode capacity but the math (12,000 BTU/hr per ton) is identical for heating capacity.

Why is 'ton' used for AC instead of kW?

U.S. HVAC commerce grew up on the ice-industry ton. The unit is colloquial shorthand: contractors, sales teams, and homeowners all share it. Engineers convert to kW for international or technical documentation.

Power conversion

BTU/hr to Tons

Convert BTU per hour to tons of refrigeration at the fixed ratio 12,000 BTU/hr = 1 ton.

1 BTU/hr8.3333e-5 RT

BTU per hour

BTU/hr

Accepts zero, positive values, decimals, and either a dot or comma decimal separator.

Tons of refrigeration

2RT

How to convert BTU/hr to RT

Three steps complete the conversion:

Find the BTU/hr value

Read the AHRI certificate, equipment nameplate, or manufacturer data sheet.

Divide by 12,000

Every 12,000 BTU/hr is one ton. The math is exact — no rounding artifacts.

Match to the contractor's tonnage scale

Residential AC sells in half-ton increments: 1, 1.5, 2, 2.5, 3, 3.5, 4, 5 tons.

Formula

BTU/hr to RT formula

BTU/hr → RT

P(tons) = P(BTU/hr) ÷ 12,000

RT → BTU/hr

P(BTU/hr) = P(tons) × 12,000

Worked example

Convert a 24,000 BTU/hr AC nameplate to tons. The result, 2 tons, is the figure a contractor uses on replacement quotes, warranty paperwork, and Manual S equipment matching.

Start

24,000 BTU/hr

Apply

× 8.3333e-5

Result

≈ 2 RT

Interactive

Scale explorer for BTU/hr to RT

Drag the slider or click a tier to see where your BTU/hr value lands on the equipment scale — with live RT output.

BTU per hour

24,000

BTU/hr

Tons of refrigeration

Closest tier:24,000 BTU/hr— 2 ton

Visual scale

BTU/hr to tonnage at common sizes

Every BTU/hr nameplate maps cleanly to a half-ton contractor size.

Linear scale

Click any bar to set as reference

Reference: 24,000 BTU/hr (2 ton). In this btu/hr to tonnage at common sizes chart, the other bars show the ratio relative to that selected value.

Fundamentals

What is BTU/hr to RT?

BTU/hr to Tons converts BTU per hour to tons of refrigeration by dividing the BTU/hr value by 12,000. AC and chiller equipment labels list capacity in BTU/hr, but contractors, schedules, and replacement quotes work in tons. The conversion is the same exact ratio either way — 12,000 BTU/hr equals one ton — but the use case is different: this page is for engineers and homeowners who have a BTU/hr number in hand and need the contractor-facing tonnage. The formula is P(tons) = P(BTU/hr) ÷ 12,000.

A ton of refrigeration is a power unit equal to 12,000 BTU/hr. It originated in the 19th-century ice industry — the rate of cooling that could replace one short ton of melting ice over 24 hours.

Although the unit comes from cooling, it measures power in either direction. A 'two-ton' heat pump moves 24,000 BTU/hr of heat regardless of whether it is operating in cooling or heating mode.

Equipment nameplates almost always lead with BTU/hr because that is the U.S. AHRI-certified test result. Contractor sales literature, on the other hand, almost always leads with tons. This converter bridges the two.

Applications

When to convert BTU/hr to RT

Real-world scenarios where this conversion shows up in engineering, HVAC, and equipment specification work.

Reading AHRI certificates

AHRI lists cooling capacity in BTU/hr; convert to tons to match the catalog model number.

Quote validation

Verify that a contractor's 'three-ton' replacement quote matches the BTU/hr on the existing nameplate.

Manual S equipment selection

Manual J calculates loads in BTU/hr — convert to tons to choose from manufacturer ton-step catalogs.

Warranty paperwork

Service contracts and extended warranties often record capacity in tons even though the install paperwork uses BTU/hr.

Commercial chiller schedules

Translate commercial cooling-tower or chiller plant BTU/hr ratings into the tonnage values used on mechanical drawings.

Guidance

Tips and common pitfalls

Tons of refrigeration ≠ tons of weight

The unit is a rate of heat removal. The name comes from the historical equivalence to a ton of melting ice per day, not from any current weight.

Half-ton steps are the contractor standard

Manufacturers build in 6,000 BTU/hr increments. A 21,000 BTU/hr load gets rounded up to a 2-ton (24,000) unit, not a custom 1.75-ton.

Don't oversize on rounding

If the BTU/hr load is 22,000, that is 1.83 tons. Manual S guidance often allows downsizing to 1.5 tons in mild climates rather than jumping to 2 tons.

Reference

BTU/hr to RT conversion table

BTU per hour (BTU/hr)	Tons of refrigeration (RT)
6,000 BTU/hr	0.5 RT
9,000 BTU/hr	0.75 RT
12,000 BTU/hr	1 RT
15,000 BTU/hr	1.25 RT
18,000 BTU/hr	1.5 RT
24,000 BTU/hr	2 RT
30,000 BTU/hr	2.5 RT
36,000 BTU/hr	3 RT
42,000 BTU/hr	3.5 RT
48,000 BTU/hr	4 RT
60,000 BTU/hr	5 RT
72,000 BTU/hr	6 RT
96,000 BTU/hr	8 RT
120,000 BTU/hr	10 RT

In practice

Industry context and practical notes

How a homeowner's quote becomes 'three ton'

A residential AC replacement starts with a Manual J load calculation — square footage, window area, insulation, infiltration, and climate produce a BTU/hr cooling load. The contractor reads this number, rounds to the nearest half-ton, and quotes the equivalent tonnage on the proposal. A 33,500 BTU/hr calculated load becomes a '3-ton' quote because 36,000 BTU/hr is the closest standard half-ton step. Homeowners never see the BTU/hr value; the tonnage is the customer-facing currency of residential HVAC.

When BTU/hr appears anyway

The equipment nameplate, the AHRI certificate, the warranty registration, and the electrical inspector's checklist all show BTU/hr. The disconnect between contractor-facing tonnage and equipment-facing BTU/hr is why this conversion is so common. A homeowner who reads '36,000 BTU/hr' on the outdoor unit and asks the contractor what that means is being given the literal capacity in the unit the engineer used during sizing. The translation back to tons happens dozens of times a day at every HVAC distribution counter.

Did you know

A standard 12,000 BTU/hr 'one-ton' AC moves enough heat to melt approximately 86 lb of ice per hour — the modern descendant of the original ice-industry definition.

Interpretation

How to interpret this result

A refrigeration ton is cooling capacity, not equipment weight. One refrigeration ton is defined as 12,000 BTU/hr, so this conversion is exact within that unit definition.

ASHRAE uses cooling capacity for the rate at which equipment removes heat, expressed in watts, BTU/hr, or refrigeration tons. Nominal tonnage identifies a capacity class; sensible capacity, latent capacity, airflow, and rating conditions determine actual field performance.

Examples

Practical calculation scenarios

Residential system

36,000 BTU/hr equals exactly 3 refrigeration tons.

Commercial rooftop unit

180,000 BTU/hr equals exactly 15 refrigeration tons and about 52.75 kW of cooling capacity.

Quality check

Mistakes to avoid

Treating tonnage as physical mass
Using nominal tonnage as guaranteed field capacity
Assuming cooling tonnage equals electrical input

Technical reference: NIST Guide to the SI conversion-factor tables. Additional terminology: ASHRAE terminology for HVAC capacity and efficiency.

Scope

Limitations and assumptions

Refrigeration tons describe cooling capacity, not equipment weight or electrical input. Nominal tonnage can differ from sensible and total capacity at actual indoor and outdoor conditions; airflow and latent load are not calculated here.

Questions

Frequently asked

Related tools

Tools related to BTU/hr to Tons

Continue from BTU/hr to Tons to the closest unit conversions, methodology, and formula guidance.

BTU/hr to kW

Convert to kilowatts for metric and European spec sheets.

BTU/hr to MBH

Commercial HVAC schedules and boiler plate ratings.

BTU/s to Watts

Per-second heat-transfer rate to SI watts.

BTU to Watts Calculator

Compare BTU/hr to Tons with the broader multi-unit power converter.

Calculator Methodology

Review the constants, validation, and rounding rules used for BTU/hr to Tons.

BTU Conversion Formula Guide

Place BTU/hr to Tons in the wider BTU/hr and watts formula context.

Trust and accuracy

Methodology and accuracy

The calculation uses the defined relationship 1 refrigeration ton = 12,000 BTU/hr. The conversion itself is exact, while displayed decimals and real equipment performance remain context-dependent. The supporting constants and review policy for the tons calculation are documented on our calculator methodology page.

Last reviewed: August 7, 2026

Calculator summary

This calculator converts cooling capacity between BTU/hr and refrigeration tons. Treat the result as nominal capacity and consult rated performance data for operating conditions and electricity use.