Home Energy & HVAC

How much does a space heater cost to run? Learn the kWh formula, real monthly costs in US, UK and AU rates, and when electric heat beats gas or a heat pump.

What dew point is, how to calculate it with the Magnus formula, and why a 50% humidity reading can still fog your windows and grow mould on cold fall nights.

Most attics have settled, decades-old insulation far below current DOE targets. Here's the R-value math for what you're missing and what topping up costs.

A bigger BTU number on the box doesn't guarantee a cooler room. Here's the actual BTU sizing formula, worked out against a real west-facing bedroom.

The 30% federal solar tax credit ended in 2025. Here's the real math on how many panels you need and whether rooftop solar still pays for itself in 2026.

How much your air conditioner costs to run per hour and per month, the simple kWh formula behind every bill, and which appliances drive summer costs.