Building a home in a cold climate, like northern Minnesota, can be a lot different than building a home in a warm climate. Selecting the wrong design, accepting not-up-to-par construction details for the climate, or opting for the wrong products (or builder) can result in an uncomfortable home that’s too cold, too drafty, or that fosters roof ice dams and icy walkways and that results in enormous energy bills.
The building systems, design considerations, acceptable products, construction practices and techniques ideal for cold climates vary greatly from those in warm climates. Below is a brief synopsis of all the items you need to check or demand from your builder.
But first, you need to do a little research. A basic understanding of how heat, air and moisture travel within the exterior walls of a home is vital. Knowledge of insulation ratings, glazing products, passive energy concepts, and energy efficient HVAC systems is key. Ask your homebuilder for help.
A ‘Systems Approach’
The Cold Climate Housing Program (CCHP) at the University of Minnesota, “Promotes a ‘systems approach’ to building in cold climates,” says Pat Huelman, associate professor and CCHP coordinator.
Situated within the Department of Bioproducts and Biosystems Engineering, College of science &.Engineering at the St. Paul, MN, campus, the CCHP was started in response to early energy efficiency recommendations that changed air tightness and insulation values but did not pay attention to the implications these had on moisture and indoor air quality. Today, says Huelman, we also have the issues of sustainability, material resource responsibility and resiliency.
The CCHP recommends a number of key components, including: thermal insulation over the entire building envelope and foundation; basement or slab waterproofing and drainage; a continuous air barrier/vapor retarder inside and continuous weather barrier outside; energy-efficient, condensation resistant windows, appliances, lighting, and HVAC system with mechanical ventilation; use of Low-toxicity materials; user friendly controls (set-back thermostat, dehumidistat and ventilation); and proper homeowner operation and maintenance.
“The systems approach,” says Huelman, “is the idea that you have to include and look to optimize the performance parameters of not only the building envelope and the mechanical systems, but also the home’s occupants. The people,” he adds, “are really important. How they operate, control and maintain the home is vital.”
The material below examines some of the construction and mechanical features, as well as the best home orientation, solar design concepts, and techniques to mitigate snow problems. The “people” issue is up to you.
Here’s what to double-check with your new home builder:
Make Sure the Building Envelop is Air Tight and Accounts for Moisture
Check the construction details on the new home plans. Ask your builder how the building envelope or exterior wall system will provide high insulation values, prevent mold-causing condensation, stop thermal bridging, and reduce heat transmittance.
In cold weather, interior moisture will flow to the outside via air leakage and vapor diffusion. Housewrap and impermeable vapor and moisture barriers or membranes and effective caulking details are essential. Check the builder’s construction details to see how they are designed to eliminate penetrations, prevent moisture condensation, and air seal exterior walls. Will the gaps around windows, doors and electrical boxes be sealed? Is the roof cavity drained and water tight? Will all joints be fully taped and openings sealed? Is the insulation “continuous”? Does the foundation system keep moisture away from the home?
Inquire About Insulation
Learn the benefits and insulation quality (R-value) of the various forms of insulation, from fiberglass batts and blown-in cellulose to rigid foam board and closed-cell spray polyurethane foam. Ask about the types and levels of insulation provided. Don’t forget about pipe insulation to prevent pipes from freezing.
Some builder’s combat thermal bridging, air, moisture and heat loss through special framing techniques, such as 2×6 construction, double wall wood framing, or raised hip insulation and other construction techniques. Others might use structural insulated panels, insulated concrete forms for concrete walls or even insulated precast wall panels. High-density materials like concrete, bricks and tiles can provide thermal mass that stores energy from the sun during the day and emits in at night.
House ventilation is also necessary to remove moisture vapor from under exterior wall and roof cladding. Does the home have a passive or mechanical ventilation system? How about an air-to-air heat exchanger? Do the roof and wall assemblies drain to the exterior? Is the bottom of the roof overhang insulated?
Pay special attention to the windows the builder provides. Are they at least double-paned? Are they low-E units? Will they have adequate weather stripping?
The National Fenestration Rating Council (NFRC) certifies and labels windows, doors, and skylights based on their energy performance ratings. NFRC product labels will show the products U-factor, Solar heat gain coefficient (SHGC), visible transmittance, air leakage, and condensation resistance. Products might also be ENERGY STAR® qualified. The Efficient Windows Collaborative provides recommended performance ratings for your climate.
Consider the Position of the Sun
Select a building site and home design that positions living area windows toward the sun, i.e. within 30 degrees of true south, although bedroom windows can face north. Make sure landscaping or other buildings will not obstruct this view. Consider smaller rather than larger window sizes.
Plan to add drapes, blinds, retractable screen systems, shutters or window shades later to prevent overheating in warm months. Cellular shades are available that feature two different opacity levels. Some builders offer shading options in their design center.
Ask your builder about any passive solar design techniques they use to take advantage of a building’s site, climate, and materials to minimize energy use. The U.S. Department of Energy defines a passive solar home as a home that collects heat through south-facing windows and retains it in materials that store heat, known as thermal mass. Ingredients include south facing windows, and a ventilation system with fans and blowers that help distribute heat.
Passive solar designs also capitalize on darker color roofs to absorb heat and “thermal mass” products such as concrete, brick, stone, and tile that retain daytime sunlight heat and release it at night. Other elements might include electronic sensing devices, such as a differential thermostat, operable vents and dampers, low-emissivity blinds, operable insulating shutters and awnings. Plans that feature a sunroom or solarium are great at capturing solar heat.
Plan for Snow
In cold climates you will also likely have to account for snow issues and snow loads in your home design. Select a home plan with a simple, steeply sloped roof, such as a standard gable. Slate and wood shingle roofing sheds snow less easily. Look for roof designs that have fewer dormer or skylight openings and that position vents and chimneys near the roof ridge or peak. Make sure that the roof edge will have an ice shield membrane.
Look for home plans with a covered entryway. Will exterior walkways be positioned away from roof overhangs? Have wide, flat walkways to easy snow shoveling and include stair railings to prevent falls when icy. Consider upgrading to add a de-icing and radiant snow melting system.
Be Energy Efficient
Upgrade your HVAC equipment to a high-energy efficiency rated system and ENERGY STAR® rated products. This may cost a bit more but will increase your home value and more than pay for itself in the long term.
This is where a little more homework is required to improve your understanding of a bunch of acronyms, including:
- EER (Energy Efficiency Ratio) of an A/C unit is the ratio of output cooling energy to the input electrical energy.
- COP (Coefficient of Performance) is a measure of the amount of power consumed by a system when compared to the amount power output.
- SEER (Seasonal Energy Efficiency Ratio) is the measure of energy efficiency of cooling equipment. EER (Energy Efficiency Ratio) evaluates the operating efficiency of a cooling unit.
- HSPF (Heating Seasonal Performance Factor) measures the heating efficiency.
- AFUE (Annual Fuel Utilization Efficiency) measures the efficiency with which a certain fuel transforms into heat.
- MERV (Minimum Efficiency Rating Value) ratings measure the efficiency of an air filter.
You may also want to ask about upgrades for whole house ventilation concepts, electronic air filters, and automatic humidifying equipment and maybe even possible options for heat pumps, radiant heat systems or residential solar panels.