The cheapest Btu is the one the house does not need
Reducing unnecessary heat gain in summer and heat loss in winter can reduce HVAC runtime regardless of which equipment is installed.
Energy Guides
Start with how the home uses energy
HVAC operating cost is a system problem: weather, building load, equipment efficiency, airflow, controls and utility rates all interact.
Energy Savings
Lower Your HVAC Energy Costs
A practical hierarchy for reducing heating and cooling energy use.
Read guide →Energy SavingsThermostat Settings & Energy Savings
How setpoints, setbacks and schedules affect runtime and comfort.
Read guide →Energy SavingsDoes a Higher SEER2 Save Money?
How to think about higher cooling efficiency and realistic payback.
Read guide →Energy SavingsHeat Pump Operating Costs
What drives heat-pump electricity use in heating and cooling.
Read guide →Energy SavingsFurnace Efficiency & Gas Costs
How AFUE, weather, load and fuel price affect heating cost.
Read guide →Energy SavingsDuct Leakage & Energy Waste
Why lost supply air and return leakage can increase HVAC consumption.
Read guide →Energy SavingsAir Sealing & Insulation
How the building envelope changes the load your HVAC system must handle.
Read guide →Energy SavingsHVAC Filters & Energy Use
Why both dirty filters and overly restrictive filtration can affect airflow.
Read guide →Energy SavingsCeiling Fans & HVAC Savings
How air movement can improve comfort without actually lowering room temperature.
Read guide →Energy SavingsHumidity & Energy Use
Why moisture control affects comfort, thermostat choices and cooling operation.
Read guide →Energy SavingsShould You Replace HVAC for Efficiency?
How to compare replacement cost with realistic energy savings.
Read guide →Energy SavingsUnderstanding Your HVAC Utility Bill
Separate weather, rate changes, runtime and equipment issues when bills increase.
Read guide →Energy SavingsBoiler Efficiency & AFUE
How boiler efficiency ratings relate to real-world fuel use.
Read guide →Energy SavingsOutdoor Reset Controls
How variable water-temperature control can improve hydronic system operation.
Read guide →Do not confuse ratings with guaranteed savings
SEER2, HSPF2 and AFUE are useful comparison metrics, but actual utility savings depend on the home, climate, usage, rates and installation.
Considering New Equipment?
Run the economics before paying for efficiency
Compare the added installed price of higher-efficiency equipment against realistic operating savings and the period you expect to own the system.
Related Resources
Continue with the right next topic
Lower HVAC Energy Costs
Start with the factors that usually matter most.
HVAC Efficiency Ratings
Understand SEER2, EER2, HSPF2 and AFUE.
Choosing HVAC Efficiency
Apply energy information to a replacement decision.