How many BTU do I need for my room in Jamaica?

A typical bedroom (12x12 ft) in Jamaica with average insulation needs approximately 5,000-7,000 BTU. Larger living rooms (15x20 ft) may need 12,000-18,000 BTU. Factors like window count, sun exposure, ceiling type, and occupants significantly affect the requirement. Use our calculator with your specific room details for an accurate estimate.

What SEER rating should I look for in the Caribbean?

For Caribbean climates where AC runs frequently, a minimum SEER of 16 is recommended. Higher SEER units (18-25) cost more upfront but save significantly on electricity bills. Inverter units typically achieve SEER 18-25 and are ideal for the Caribbean's sustained cooling demands.

How much does it cost to run an AC in the Caribbean?

Running a 12,000 BTU (1 ton) split AC for 8 hours daily costs approximately J$8,000-12,000/month in Jamaica, TT$150-250/month in Trinidad, or US$30-50/month in the Bahamas. Actual costs depend on your electricity rate, unit efficiency (EER/SEER), and usage patterns.

A/C Load Calculator - Caribbean Cooling Load Sizing (BTU)

New to this? Plain-English guide

BTU (British Thermal Unit) — the standard measure of cooling power. A small bedroom needs roughly 6,000-8,000 BTU; bigger or sunnier rooms need more.

Ton (of cooling) — another cooling unit: 1 ton = 12,000 BTU. A "1.5-ton unit" is an 18,000 BTU air conditioner.

Outdoor Design Temperature — the hottest weather the AC is sized to handle. Set for your location so the unit copes on the worst afternoons, not just average days.

Insulation Quality — how well the room holds its cool air. Poor insulation (thin walls, gaps, single-pane glass) forces a bigger unit for the same room.

Building Configuration

Location

Insulation Quality

Building Sun Exposure

Units

Currency

Rate per kWh

Auto-populated typical rate. Actual rate varies with fuel surcharge — check your bill.

Operating Hours/Day

AC Unit Type

Rooms

Project Management

Load Saved Project

Calculation Method: Base BTU = area × insulation factor. Adjusted for ceiling height, windows (solar gain by orientation), occupants, heat sources, ceiling/floor type, sun exposure, and climate delta. Recommended unit rounded up to nearest standard size.

WattWorks Design - Caribbean HVAC Experts: Serving Jamaica and the Caribbean with professional HVAC design, electrical engineering, and technical consultation. Need a detailed cooling load assessment? Visit WattWorks Design

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A/C Sizing Guide

What is BTU?
BTU (British Thermal Unit) measures cooling capacity. One BTU is the energy needed to raise 1 pound of water by 1°F. Air conditioners are rated by how many BTU/hr they can remove from a space. A 12,000 BTU unit = 1 ton of cooling.

Caribbean Climate Considerations
The Caribbean experiences year-round high temperatures (88–95°F) and humidity (60–85%). This means:

AC units work harder and longer than in temperate climates
Humidity removal is as important as temperature reduction
Oversizing wastes energy; undersizing leaves rooms uncomfortable
Sun exposure and window orientation significantly affect load

Insulation Quality Guide

Rating

BTU/sqft

Description

Poor

Concrete block, no ceiling insulation, metal roof

Average

Basic ceiling insulation, standard construction

Good

Wall + ceiling insulation, double-pane windows

Excellent

Full insulation, radiant barrier, Low-E windows

SEER / EER Ratings

EER (Energy Efficiency Ratio) = BTU/hr per watt at a single test point
SEER (Seasonal EER) = average over a cooling season
Window units: EER 8–12 (SEER 10–14)
Split units: EER 10–15 (SEER 14–21)
Inverter splits: EER 12–18 (SEER 18–25)
For Caribbean, minimum SEER 16 recommended for cost savings

Window Selection & Solar Gain
Windows are a major source of heat gain:

Single Pane: 100% solar heat gain (worst)
Double Pane: 75% of single pane gain
Tinted / Low-E: 55% of single pane gain (best)
West-facing windows get the most afternoon sun (700 BTU/window)
South-facing windows get the most total sun (800 BTU/window)
North-facing windows get the least sun (400 BTU/window)

Standard AC Unit Sizes

BTU

Tonnage

Typical Use

9,000

0.75 ton

Small bedroom

12,000

1.0 ton

Bedroom / small office

18,000

1.5 ton

Living room / large bedroom

24,000

2.0 ton

Large living area

30,000

2.5 ton

Open plan area

36,000

3.0 ton

Large commercial space

48,000

4.0 ton

Commercial / warehouse

60,000

5.0 ton

Large commercial

Tips for Reducing Cooling Load

Add ceiling insulation (can reduce load 15–25%)
Install tinted or Low-E window film
Use light-colored roof paint or coatings
Plant shade trees on west and south sides
Seal gaps around doors and windows
Use ceiling fans to supplement AC
Keep curtains/blinds closed during peak sun hours
Service AC units regularly (clean filters monthly)

Disclaimer: This calculator provides estimates for preliminary AC sizing. Actual cooling requirements depend on site-specific conditions including exact location, building construction, humidity levels, internal heat loads, and ductwork design. Always consult a qualified HVAC professional for detailed cooling load analysis and equipment selection.

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Total BTU Required

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Total Tonnage

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Total Monthly Energy

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Total Monthly Cost

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Total Annual Cooling Cost

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Recommended Minimum SEER

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