How to Identify Your Home Systems

This guide helps homeowners identify their heating system, cooling system, water heater, insulation level, window type, and light bulb type -- all without calling a contractor. Use it alongside your EcoAudit energy audit.

Heating Systems

Gas Furnace

A large metal box in the basement or utility room with a flue pipe exiting through the wall or ceiling. A gas supply pipe (yellow flexible hose or black iron pipe) connects to the burner at the bottom. Very common in cold-climate U.S. homes.

Electric Furnace

Identical shape to a gas furnace but no flue pipe exits the top. Only electrical wires enter the unit. Listed as 240V on the data plate. Common in all-electric homes or areas without natural gas service.

Heat Pump

Always has an outdoor compressor unit on a concrete pad. Key difference from central A/C: the outdoor unit runs in winter as well as summer. Inside, there is an air handler or wall-mounted heads (mini-split).

Boiler / Radiator System

Homes with boilers have cast-iron radiators standing against walls or fin-tube baseboard units. There are no ducts or air vents. The boiler itself is a large unit in the basement with pipes running to each room.

Electric Baseboard

Long thin heaters (2-8 ft) mounted at floor level along exterior walls. Each room has its own unit with its own thermostat. No ductwork, no outdoor unit.

Cooling Systems

Central Air Conditioning

A square outdoor compressor on a concrete pad plus air vents throughout the house. The outdoor unit only runs in summer. If it runs in winter too, you have a heat pump.

Mini-Split / Ductless

Wall-mounted indoor heads (slim rectangular units near the ceiling) connected by refrigerant lines to a small outdoor unit. No ductwork required.

Water Heaters

Gas Tank

Tall cylindrical tank with a flue pipe on top and a gas supply line at the bottom. Most common water heater type in the U.S.

Heat Pump Water Heater (Hybrid)

Taller than a standard tank, with a fan and coil unit on top. Makes a humming noise. Uses 3x less electricity than a standard electric tank.

Tankless

Wall-mounted box, much smaller than a tank heater. Heats water on demand with no storage tank. Can be gas or electric.

Insulation Levels

Open your attic hatch and use a ruler to measure insulation depth. Less than 4 inches is Poor. 5-10 inches is Average. 12 or more inches is Good. Bare joists with no material means None.

Window Types

Look at the edge of the glass where it meets the frame. A single glass line is single pane. Two glass lines with a spacer bar between them is double pane. Three lines with two spacers is triple pane. Low-E coating is often marked with a small etched stamp in the corner.

Light Bulb Types

LEDs have a plastic heat-sink base with fins. CFLs have a distinctive spiral tube shape. Incandescents have a thin glowing filament visible inside the glass. Halogens are often PAR or BR shaped, used in recessed can lights.