Exterior Walls and Insulation

• Frame corners with two studs, instead of three, to allow more space for insulation.
• Use advanced wall framing techniques, including 24-inch on-center framing.
• Air seal building cavities before installing any insulation; it is required to achieve the full insulation value.
• Consider blown-in insulation as it typically provides better performance than batts.
• Look for fiberglass and formaldehyde-free options when buying insulation.
• Ensure your contractor can deliver “ENERGY STAR Grade 1” insulation to maximize performance.
• For new walls, consider panelized wall construction or modular construction for reduction of waste during construction.
• Construct and insulate walls to have an R-26 Rating
• Most homes in the U.S. built before 1970 are poorly insulated, if at all. Modern energy codes require minimum levels of insulation, but it’s possible you could do more to save money on your energy bill.
• Even with progressive energy codes, some energy-efficient building details are overlooked in many new homes.

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Framing tips

• For new walls, consider panelized wall construction or modular construction for reduction of waste during construction.
• Use the advanced wall framing technique of 24-inch on-center framing, which saves lumber and allows for increased insulation. This method also incorporates two stud corners, insulated headers and oversized or raised trusses to allow for more attic insulation.
• Window and door headers are typically uninsulated, however, insulated headers are readily available and reduce energy use for heating and cooling.

Insulation levels and types

• When faced with the choice of ceiling or wall insulation, many homes get better performance by starting with the ceiling first. Consult a Home Performance Contractor for a detailed analysis.
• Some houses may contain vermiculite insulation, which looks like shiny brown rocks, roughly the size of peas. This insulation potentially contains asbestos and could be a health hazard if disturbed and inhaled. Sample the vermiculate and send it to a lab for asbestos testing.
• Consider increasing the amount of insulation in your home with a blown-in insulating product. Blown-in insulation can be cellulose, foam, fiberglass or rockwool.
• Insulation products are rated by their resistance to heat flow, called R-Value. The higher the R-Value number, the more effective the insulation and the lower your energy bills.
• Use cellulose rather than fiberglass for insulation. Fiberglass has eight times the embodied energy as cellulose. Cellulose is made from 80 percent recycled newspapers and cardboard. The other 20 percent is borate, which resists mold growth, repels insects and retards fire. Avoid cellulose insulation with any ammonia-based additives.
• If you choose to use fiberglass be sure to select a formaldehyde-free product. Major brand formulations are also available with more than 50% recycled content.

Installation tips

• Take precautions when insulating on top of, or near, existing wiring, fixtures, chimneys and flue pipes. Your permitting jurisdiction may offer guidance on this topic. If your house has any “knob and tube” electrical wiring, have a licensed electrician evaluate its condition and see whether it is safe to add insulation on top of it.
• Install insulation baffles at soffit vents before insulating – this protects insulation from degradation and reductions in R-value though wind washing. Wind washing leads to cold spots and in extreme cases can cause moisture problems.

Air sealing tips

• Air seal around any penetration in the ceiling such as IC/AT rated can lights, fans, and electrical and plumbing penetrations. Air seal the small gap between ceiling drywall and top plates.
• Recessed can lights are often a major source of air leakage and not all can have insulation against them. If you’re looking to insulate an attic and have recessed can lights, look at the label on the inside of the can. Look for “IC Rated”. If the can is not IC Rated, you will need to have heat-resistant boxes built around every recessed light in the attic before adding insulation. If they are IC rated, insulation can be applied directly over them.
• Sheet metal barriers should be installed between insulation and hot surfaces such as chimneys and other combustion appliance vents. Air sealing at these locations can be done with special caulks.

Exterior Siding

• Install rigid insulation on the exterior and/or a rain screen before installing new siding.
• Where possible, use siding with reclaimed, or recycled material on at least 20% of solid wall surface.
• Look for 50-year siding for increased durability.
• For new wood siding, prioritize salvaged wood that is properly treated with non-toxic finishes or third party certified sustainably harvested wood siding.
• Non-wood siding alternatives include fiber cement board siding, aluminum and stucco.
• Seek alternatives to vinyl siding and exterior trim.
• For any new siding, install a rain screen. This is a capillary break between siding/trim and building paper or house wrap.

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Planning and installation

• If your siding is old or failing, be sure to replace it (and the exterior sheathing if necessary) before adding insulation to the walls from inside. This sequence will prevent your wall assembly from getting wet, thereby preventing mold issues and decay.
• If replacing siding and/or exterior trim, do not use vinyl siding or vinyl exterior trim. Use siding with reclaimed, or recycled material on at least 20% of solid wall surface. Consider using 50-year siding product for new or replaced siding.
• If replacing siding, consider adding two, staggered layers of rigid exterior insulation to the outside of the sheathing. This will greatly improve the insulating value of your walls. Give preference to a rock wool product rather than a foam product for fewer environmental impacts.
• Install a rain screen to increase a wall’s ability to dry out in the presence of wind driven rain – a boost to moisture damage, insect damage and other problems. Rain screens are compatible with most siding products.

Seek alternatives to vinyl siding

• While inexpensive, vinyl carries considerable issues for environmental and human health, especially during manufacture and disposal. Vinyl is not biodegradable, and is generally not recyclable.

Entry

• Place a washable doormat and a shoe rack in your entryway.
• Remove shoes at the entry door and wear slippers or "indoor shoes" in the home.
• Consider how a mud room could be integrated to further reduce tracked-in contaminants.
• Keep an emergency preparedness plan (earthquake, fire, flood, etc), including contacts for neighbors & family, near the entry or at an easily accessible location.
• Encourage the removal of shoes at your front door. The majority of indoor air pollutants are tracked in on shoes, including moisture, pesticides, fertilizers, automotive fine particulates, spores and pollen.
• Provide sufficient space for storing shoes and consider a comfortable chair or bench as a place to put on and take off shoes.
• Save energy by properly sealing your home against air leaks under sill plates, around windows, doors, framing members, and electric, plumbing and mechanical penetrations. For doors, bristle weatherstipping is more durable than the bulb type, especially around pets.
• Build an emergency kit and keep it in a place that is accessible and known to all in the household. This location may not be in the home, but near the entry. Keep an emergency preparedness plan (earthquake, fire, flood, etc.), including contacts for neighbors & family, near the entry or at an easily accessible location. Learn more from King County’s Emergency Management page.

Windows

• Ask a Home Performance Contractor about repairing or replacing your old windows.
• If you have single-paned windows, add storm windows or replace with double-paned.
• If your home is on a historic register or has landmark status do your research before buying new windows.
• If purchasing new windows, look for products with a “U-value” of 0.30 or less.
• Install shading over windows on the exterior of the house to limit solar heat gain.
• For new windows, consider National Fenestration Rating Council (NFRC) certified options.
• Position operable windows for optimized cross ventilation
• For new windows, install a sloped sill pan with end dams and back dams & install metal flashing
• Use no VOC, low-VOC, or low-toxic interior paints and finishes for all surface areas (including interior windows, trim)
• Seal around edges of window penetrations with non-/low-toxic sealants
• Replacing windows is one of the last upgrades you should make to your home. On a square footage basis, windows are one of the most expensive improvements you can make and they make up a far smaller total area than your floors, walls and ceilings.
• In addition to limited energy savings, replacing windows typically provides limited cost savings, with a simple payback of anywhere from 40 to 80 years, depending on how leaky your initial windows are and how well-sealed the new ones are.
• While new windows are low on the list for cost effective investments, there are many other reasons to install new windows which may be of greater benefit.

Window repair

• Repair windows that have been painted shut so they are fully operable.
• Old, counterweighted double hung windows leak significant amounts of air through the pulleys on either side of the frame. Place specially designed pulley seals to prevent cold air infiltration.
• Weatherstrip the meeting rail of double hung windows.

New window selection and installation

• Replace “failed” windows that have moisture between the panes.
• When replacing windows, use backer rod and low expansion foam to seal gaps between the window frame and the rough opening. Always consult with the window manufacturer before using ANY expanding foam. Some manufacturers will void the warranty if the wrong foam is used.
• Consider installing solar light tubes, a kind of skylight, to bring in more natural light.
• If installing new windows, choose products with low-E coatings and U-values less than 0.30 to increase comfort. U-value dictates the heat transfer rate – how efficient it is at slowing down heat movement in or out. The lowest value is best.
• Look for windows with a higher VT (visible transmittance), which allow more sunlight into your home.
• Prioritize wood windows with third-party certified sustainably harvested wood when possible for new or replacement windows. Start with National Fenestration Rating Council (NFRC) certified options. Extruded fiberglass composite windows are also dimensionally stable, extremely durable, hold their color well over time and can also be good energy performers. A final option to consider are wood composite windows, which contain recycled polyvinyl chloride or high density polyethylene and wood waste fiber to provide the thermal insulation of wood and have the decay resistance of plastic.
• Flashing should be installed over all windows. The windows should be oriented so that the small holes or drains in window frames are at the bottom.
• Install overhangs over windows on the exterior of the house to limit solar heat gain in the warmer months while still allowing free heat gain in cooler months. Overhangs are recommended for windows oriented within 30 degrees of due south.
• Use no VOC, low-VOC, or low-toxic interior paints and finishes for all surface areas (including interior windows, trim)
• Seal around edges of window penetrations with non-/low-toxic sealants

Front Door

• Weatherstrip your door including an air-tight door sweep at the bottom.
• For weather protection of new exterior doors, add back dams and install metal flashing at heads of doors
• Use no VOC, low-VOC, or low-toxic interior paints and finishes for all surface areas (including interior doors, trim)
• Seal around edges of door penetrations with non-/low-toxic sealants

Built Green

• Confirm your project goals: do you need to add on or could you reorganize your space or downsize your stuff?
• Check with your local jurisdiction or King County for applicable permits and code requirements.
• Consider going up instead of out.
• Develop a budget that shows the longer term and operational savings gained from upfront strategies. Higher initial cost may result in long-term savings.
• Get ideas from the Built Green Remodel Certification checklist Download PDF - 598KB PDF.