Megawatt to BTU (IT)/hour

In the US, roughly 750–1,000 homes (average consumption ~1.2 kW per home). In Europe, where usage is lower, 1 MW can serve 1,500–2,000 homes. But this is average — on a hot summer afternoon when everyone cranks AC, that number can drop to 300–400 homes. Grid planners must size for peak demand, not averages, which is why installed capacity far exceeds average load.

A small data center uses 1–5 MW; a large hyperscale facility (Google, AWS, Microsoft) draws 50–200 MW — some exceeding 300 MW. The entire US data center industry consumed about 17 GW in 2023, roughly 4% of national electricity. AI training clusters are pushing demand higher: a single large GPU cluster can draw 50–100 MW, and planned AI-focused campuses target 1 GW or more.

Onshore turbines typically rate 2–6 MW; the latest offshore monsters reach 14–16 MW per turbine. Vestas' V236-15.0 MW turbine has a rotor diameter of 236 meters — wider than two football fields. A single sweep of its blades can generate enough electricity for a UK household for two days. Capacity factors run 25–45% onshore and 40–55% offshore, so actual average output is roughly half the nameplate rating.

Most operating reactors produce 500–1,400 MW of electrical power. The world's largest, at France's Gravelines plant, has six reactors totalling 5,460 MW. Small Modular Reactors (SMRs) being developed target 50–300 MW each. Nuclear plants run at 85–95% capacity factor — far higher than wind (~35%) or solar (~25%) — meaning a 1,000 MW reactor actually delivers about 900 MW on average.

MW tells you the maximum instantaneous power the battery can deliver (how fast it can discharge), while MWh tells you total stored energy (how long it can sustain that output). A 100 MW / 400 MWh battery can deliver 100 MW for 4 hours, or 50 MW for 8 hours. Grid operators care about both: MW for handling sudden demand spikes, MWh for sustained backup during extended outages or evening solar fade.

The classic rule: 20 BTU/h per square foot. A 300 sq ft bedroom needs about 6,000 BTU/h; a 500 sq ft living room about 10,000 BTU/h. But this varies wildly with sun exposure (+10% for south-facing), ceiling height, insulation quality, number of occupants (+600 BTU per person), and climate zone. A room above a pizza oven in Phoenix needs more than a basement in Seattle. When in doubt, oversize slightly — an undersized unit runs constantly and never reaches setpoint.

Undersizing is obvious — the unit runs constantly and never reaches the thermostat setpoint on hot days. But oversizing is worse in subtle ways. An oversized AC cools the air quickly then shuts off before removing enough humidity, leaving you with a clammy 72°F house. The short cycles also wear the compressor faster (startup is the hardest moment) and waste energy. A 1-ton oversize in a humid climate like Florida can raise indoor humidity from a comfortable 45% to a muggy 60%. Proper Manual J load calculations matter more than most homeowners realize.

By definition, one ton of refrigeration is exactly 12,000 BTU(IT)/h, giving approximately 3.517 kW of cooling power. The name comes from the historical cooling effect of melting a short ton of ice over 24 hours. That physical origin should not be confused with an exact claim about the latent heat of every ice sample; this converter uses the fixed International Table BTU relationship.

Modern units achieve 12–25 BTU/h per watt of electricity (SEER 12–25). A SEER 20 unit removes 20 BTU/h of heat for every watt consumed — effectively a 3:1 heat pump ratio. That 12,000 BTU/h window unit draws 500–1,000 W of electricity depending on efficiency. The best mini-splits achieve SEER 30+, removing 30 BTU/h per watt, making them cheaper to run than resistive electric heaters even in heating mode.

A gas furnace's BTU/h rating is its thermal output after combustion efficiency losses (typically 80–96% of fuel input). A heat pump's BTU/h rating is the heat delivered including energy moved from outside — at COP 3, a heat pump delivering 36,000 BTU/h uses only 12,000 BTU/h worth of electricity. This makes direct BTU/h comparisons misleading: a 60,000 BTU/h furnace and a 60,000 BTU/h heat pump deliver the same heat, but the heat pump uses one-third the energy.