Home Performance & Energy Efficiency Articles

chart of effects of humidity on the indoor environment

Controlling Moisture & Humidity in the Home →

Moisture generally appears in two forms, liquid and gas (vapor). Some amount of moisture is always present in the air. This moisture presence is referred to as Relative Humidity (RH). 0% RH would mean there was absolutely no moisture in the air and is largely theoretical.

high performance air conditioning from Trane

How is High Performance AC Different? →

When a house or component of a house is “built to code”, that can often mean that it is as bad as it is legally allowed to be, not that it is the best it can be or utilizes current technology. Air conditioning is one system in most homes where minimum code requirements.

Why Hybrid Water Heaters are Better

Why Hybrid Water Heaters are Better →

Second to heating and cooling spaces, water heating is the largest consumer of energy in most US households. Water heating consumes 18% of energy used in homes nationwide, as of 2009, and over 95% of all water heaters installed in 2006 were traditional tank heaters…

a technician tagging a zone in a new furnace install.

Zoned Systems – It’s Different Now →

Forced air gas furnaces and air conditioning systems – and their accompanying maze of ductwork – have become nearly ubiquitous in U.S. housing stock. Many larger homes feature multi-zone heating systems, where a single furnace and duct system utilize a system of dampers and thermostats to…

UltraTouch installed underfloor

Why Use UltraTouch Insulation? →

Most homes built before 1989 were constructed without floor insulation. “Heat rises” was the theory, so attics were insulated, then walls. In reality, while warm air does usually (but not always!) rise, heat itself does not rise – it simply moves from warm areas to cold areas.

air sealed air infiltrations in the attic

Why Does Air Sealing Have to Happen Before Insulation? →

As the home performance contracting industry moves to improve the energy efficiency, comfort, safety, and health of existing homes by applying building science principles, one of the most ubiquitous problems building analysts are finding is that, even recently…

heat loss from furnace and ducts

What’s the Deal with Duct Leakage? →

Nationwide, about 85% of homes use a central forced air duct system to deliver heating and cooling to the home. Unfortunately, according to US Department of Energy, “In a typical house, about 20 to 30 percent of the air that moves through the duct system is lost due to leaks…

a crew member blowing in attic insulation

What is the Best Attic Insulation Product for My Home? →

Adding attic insulation is a no-brainer for homeowners who want to keep comfortable year-round while saving energy. In fact, this measure is required in to be installed or approved whenever a home is bought or sold in Berkeley, CA. Insulation helps slow the movement of heat…

an example of an EnergyGuide label

What Brand & Model is the Best Home Furnace? →

Ask three heating contractors which company makes the best home furnaces, and you are likely to get three different answers – maybe more! Heating contractors often align themselves with a particular manufacturer or distributor in order to secure better pricing terms,

poor installed fiberglass insulation

The True Impact of Sub-Par Insulation →

Even if there is some fluffy material in your attic, there is most likely a lot of room for improvement. In fact, poor installation, even over a small area of a home, compromises the effectiveness of your attic insulation greatly. Even if your energy audit report says that you have an appropriate…

new energy efficient windows and doors installed

The Many Benefits of New Windows →

Windows are a controversial topic in the green building world. Most homeowners assume that their windows are the biggest drain on heating and cooling energy efficiency in their home, and the biggest gains in energy efficiency can be made by replacing old windows.

surface temperature affects comfort

Surface Temperatures & Comfort →

Heating and cooling consume more energy than any other residential application – 47% of all energy consumed by homes goes to heating and air conditioning as of 2009, according to the Energy Information Administration (EIA). EIA also reports that US household…

a right-sized, energy efficient furnace installed

Should I Care About an Oversized Furnace? →

The bottom line is that, yes, you SHOULD care about an oversized furnace. Furnace oversizing has been a common practice among heating contractors for as long as heating systems have been installed in homes, and is still rampant today. However, in the last 30 years…

a properly installed vapor barrier that keeps moisture out of the living space

How Does a Crawl Space Vapor Barrier Help? →

Most homeowners don’t pay much attention to what’s going on down in their crawl spaces, and few, if any, are excited by the prospect of spending money to improve their crawl spaces. However, the crawl space is an integral component of the inter-related systems.

NFRC label

Choosing Windows →

One of the most common reasons that homeowners replace windows is for improved aesthetic appeal. But there is a lot more to look for when choosing windows for an installation project than appearances. To get the most value, safety, comfort, and energy performance…

furnace and ductwork air flow diagram

Can a New Duct System Improve Indoor Air Quality? →

In most homes, the duct system moves more air than any other system or force present in the home. Nationwide, about 85% of homes use central forced air systems – furnaces/AC and ducts – to heat and cool the living space. Most forced air HVAC systems move…

forced air heating diagram

Home Heating Alternatives to Traditional Forced Air →

Nationwide, about 85% of homes have central heating systems installed. Most of these systems are gas forced air systems, which use a gas furnace with a fan to circulate warm air throughout the home. Despite its ubiquity, gas forced air heat is not necessarily…

dense pack insulation being blow in from exterior

How Does Dense Pack Insulation Work? →

Dense Pack, or Drill and Fill, refers to a method of insulating the exterior walls of a home by blowing loose fiber insulation, usually cellulose, into the wall cavities at high pressure. Though it is necessary to drill holes into every wall cavity in order to fill the cavities…

an example of a Manual J report

Mechanical Engineering – What’s that? →

Traditionally, Heating, Ventilation, and Air Conditioning (HVAC) contractors have used rule of thumb based on square footage to determine what size furnace to install in a home. Duct systems have typically been designed on site, with layout and duct sizing based on reference tables…

an example of an open interstitial space between floors

Seal Tight & Ventilate Right →

As the home performance contracting industry moves to improve the energy efficiency, comfort, safety, and health of existing homes by applying building science principles, one of the most ubiquitous problems building analysts are finding is that, even recently…


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