Defy Six Enemies of Heat Loss in Homes
Buying or building a new house is the most significant investment we in our lives. Providing warmth and comfort should be a precondition of any home, yet most homes fall short and are coupled with hefty energy bills to make them habitable. Simply, being comfortable will make you happy, healthy, and productive. Knowing your enemies of heat loss will help you recognize true quality construction making sure you don’t end up with a gas guzzler and protect you from your thermal discontent. If you are building a new house, this is your opportunity to build a home that performs better than most on the market. If you’re buying an existing house, knowing what to look for will help you make sure heat loss won't bring you down.
1. Uncontrolled Air Leakage
A refrain by many contractors and misguided homeowners that a house has to “breathe,” however, uncontrolled air leakage is the weakest link in energy performance of a home. It could account for over 35% increase in your heating demand, or the equivalent of leaving a door open in the middle of winter! Along with wasted energy, it poses comfort, mold, moisture, and durability concerns. The best way to provide excellent air quality while avoiding these issues is to build your house as tight as possible and install a high efficiency Heat Recovery Ventilator that will provide you continuous fresh air preheated by the warmed air going out – Build it tight, ventilate right. Air tightness is a measure of construction quality – to make sure you get what you pay for. This can be verified by a Blower Door Test completed just before dry wall is installed. This will provide you with an opportunity to determine how well your building is doing and the one-time chance to seal up leaks to make it tighter.
2. Thermal Bridges
Imagine driving on a free-flowing bridge that helps you get from one side to the other without anything in your way. That’s what’s happens to heat in many places in a house as it moves from inside to outside. This is allowed to happened because there is no insulation slowing the heat loss down. Thermal bridges bypass all of the insulation you installed diminishing how well your whole house retains heat. The most typical places are where slabs meet foundations, pipe penetrations, balconies that are connected to the house, framing studs and particularly corners, in window frames and installations, and where floors and roofs meet walls. Most thermal bridges are avoidable through good, detailed design at little to no additional construction cost.
3. Lack of Insulation
How much insulation is enough? If you’re building to existing building codes the answer is not nearly enough. That is because you can’t fit nearly enough insulation in those puny wall studs of a typical house. This forces your house to be a furnace junkie just to keep you warm. Insulation is among the cheapest building materials, yet why is it used so sparingly?
Once you looking beyond minimum code studs you open a world of possibilities to add as much as you need with minimal incremental costs. Imagine the performance boost of needing over 70% less heat than what’s being built today? Our Passive Houses are optimized to put as much insulation under the slab and floors, in walls, and above ceilings as need to give the greatest benefit. The result? Intense comfort and trading in the puny walls and hungry furnace for a puny heating system.
4. Poor Windows, Installed Poorly
Windows provide a lot of benefits to homes. They provide a nice view, light, access to fresh air, and can even heat your house. While windows have these fantastic benefits, they should be handled strategically. Windows can be the most expensive item in a house. They also have the lowest insulating value meaning windows in the wrong places can be a costly enemy of heat loss as well as overheat your house in the summer. You don’t want to mess around or over do it. Do not buy the cheapest windows. All windows are not the same despite the generic testing data posted on websites. Read our window blog post for details on selecting a window. Generally, find the best triple pane windows you can find and get those quoted. The number one thing that will influence price is the quantity and size of your windows. Use them strategically:
Use big windows for big views
Reduce or avoid windows in rooms where windows will provide little benefit
Avoid tiny windows that provide little value
Bear in mind windows in the south are most beneficial for passive heating, east and west facing windows can provide some beneficial heat gain but, should be carefully shaded for spring and fall equinox. North facing windows are energy losers year-round, use sparingly if necessary.
It’s not just about glass performance, frames, spacers and installation all create weak links that should be optimized.
Installation details are critical to make sure your window performs. Make sure it’s well detailed to avoid the other enemies: air leakage and thermal bridges.
5. Inefficient Heating Systems
It’s not hard finding energy efficient equipment these days. There are also rebate programs supporting efficient appliances and heating systems. When selecting equipment make sure you compare the performance of models. Also, don’t marry yourself to a particular type of system like radiant floors or a certain furnace that is specified for a conventional home. Prepare for a mind shift: when building for energy performance, it’s how well you’ve done in insulating, avoiding thermal bridges, and air sealing your house that counts. After you have done all of these things determine how to best heat your house. At this point throw preconceived notions out the window. You can become indifferent to your energy source since you need so little. There are many options that can actually significantly avoid costs of conventional equipment.
6. Range hoods, Dryers, Bathroom Fans Dumping Warm Air Outside
Cooktop Range hoods, clothes dryers, and bathroom exhaust fans are high-powered devices specifically designed to suck the air you just paid to heat out as quickly as possible. In a world where more horsepower and badass looks is seen to be better, it’s time to get grounded about what we expect these devices to do for you and their place in an energy efficient home.
Range hoods remove pollutants, odours, and moisture. Typically, they are exhausted directly without heat recovery. In a Passive House, range hoods can be removed all together. The building code requires additional ventilation for natural gas ranges. If we remove the natural gas range from the equation to a superior performing electric induction range, your range hood is left with the job of a bathroom fan. Remember that in a Passive House, you are already getting continuous ventilation, so you’re pulling out and bringing in more fresh air than in a conventional house. That system has a boost setting for exactly those instances when you need more ventilation. Simply by locating the exhaust from the HRV greater than 8 feet away from your stove and having a switch to boost the ventilation you can avoid this enemy of heat loss.
A dryer used in most homes in North America requires a vent to outside in order to do its job. It’s costly and acts like a vacuum sucking air out of your house. It also limits you to put the dryer on an outside wall, a prime location for living spaces. Simply it’s an avoidable weak link that can save you construction and operating costs when trying to achieve Passive House performance. The energy and cost penalty of conventional dryers are so steep that they are rare in Europe and in-fact banned in Switzerland as of 2012. The alternative is a Vent-Less Condensing Heat Pump Dryer or as Europeans simply call them – Dryers. Dryers can be placed in any room in a house, use significantly less electricity, save your clothes by not cooking them, and modern models now available in North America are achieving very high consumer reviews. Combination washer / dryer units are available saving valuable square footage and the need to transfer clothes.
Bathroom fans are the most regular sources of exhaust and should be tied to a heat recovery ventilator. Don’t be a victim (as we have seen just recently on a project site that has an HRV!) of dedicated direct to outside exhaust fans installed in each bathroom by an oblivious installer.
It’s 2017, and well past the time to end these crimes against energy efficiency. We hope this post will help your vigilance and is shared to prevent others from falling victim.