I’m considering getting a whole-house ventilation system. I’ve heard the terms Energy Recovery Ventilation and Heat Recovery Ventilation used for these systems. Are they the same? If not, which one is better at saving energy?

For readers who aren’t familiar with these systems, I’ll explain that they remove stale indoor air and bring in fresh outdoor air through ductwork that is installed throughout a home. These systems save energy in the wintertime because they transfer heat from outgoing air into incoming air.

As for your question: Energyrecovery ventilation systems (ERVs) and heat-recovery ventilation systems (HRVs) have one key difference. While both recover a portion of the heat from outgoing air, an ERV also recovers moisture. Due to this difference, ERVs can have higher efficiency ratings and HRVs are able to remove more moisture from a building.

Because of the potential for moisture-related problems in buildings, including wood rot and allergens like mold and mildew, it’s important to consider more than energy efficiency when choosing between an ERV and HRV. One of the primary functions of ventilation is to remove moisture, so an HRV is likely to be the appropriate choice in our climate unless a space needs a significantly high amount of ventilation. In a case like this, an ERV can do the job without excessively drying out the air.

In either case, the efficiency of the motor has a big impact on energy use. Ventilators with variable speed brushless DC motors (sometimes referred to as ECM motors) will use considerably less electricity to operate than models with standard motors. A contractor specializing in heating, ventilation, and air conditioning (HVAC) can tell you more about these systems. Best of luck!

-Kathleen for The Home Team

Which uses less electricity; power tools that you plug in or ones that are cordless and you have to recharge?

For a given amount of work, most portable power tools (corded or not) will use about the same amount of energy. So, the difference would be in the amount of electricity used directly (for the plugged-in tool) versus what’s used to recharge the battery of a cordless tool. The two energy uses are nearly the same; recharging uses a very small amount more. Bottom line: If you’re trying to choose between the two tool options, energy use won’t be a deciding factor.

While the added energy use of a cordless power tool is negligible, the overall impact of battery charging can be notable in a typical U.S. household. That’s because many people aren’t aware that chargers draw energy as long as they’re plugged in. That wasted energy can really add up in a home with multiple portable devices, like rechargeable tools, phones, cameras, laptops, hand-held vacuums, and more. To eliminate this money waster, charge your batteries just until they’re full, and unplug the charger when it’s not in use.

- Li Ling for The Home Team