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The darker side of energy efficiency

The dark side of energy efficiency

In the middle of the winter, it’s easy to find the drafts in your home. Sealing drafts can improve your energy efficiency, but there are some important considerations to think about. Building contractors talk about the “thermal envelope.” If you haven’t heard the term, it refers to the “tightness” of a building’s enclosure. The tighter the enclosure is, the less air travels between the building’s inside and its outside.

Energy efficiency requires ventilation improvements

Gaps can naturally occur between the foundation and the home’s structure. They also commonly occur in the attic, where the roof joins the walls. Windows, doors, vents and other openings degrade the thermal envelope. These hidden openings enable air to travel freely between the home’s exterior and interior. That means your warm air in the winter, and cool air in the summer will dissipate. This raises the cost of your heating and cooling bill, and admits unwanted moisture into your home.

Conventional wisdom said that these gaps helped to control the growth of mold and mildew. That is true. But it also means that older homes are draftier, leakier and cost more to heat and cool. If you decide to seal drafts in your home (which will decrease your energy usage), test your home’s ventilation! You may need to add supplemental ventilation to avoid moisture build-up and other problems.

Your water heater can’t go it alone

One of the big targets for energy efficiency is upgrading the furnace. Older furnaces aren’t energy efficient, so they consume a lot of fuel. Traditional furnace designs vented the by-products of combustion out the chimney. (“By-products of combustion” = carbon monoxide.) Newer heating equipment may instead vent flue gases out of the side wall of the home. This may have implications for your water heater and you!

A furnace is a big piece of equipment, and it can create a generate a big draft in the chimney. This air movement enables the flue gases to escape the chimney. If you have a gas water heater, it may also vent out the chimney. It probably leans on the furnace to create enough draft to expel its products of combustion safely. If you upgrade your furnace but leave your water heater standing, your water heater may not be able to generate enough draft to clear the chimney of noxious gases.

This can set up a dangerous situation known as back drafting. Back drafting allows the nasty, noxious gases to pool in the chimney, or worse, escape into the house. This can cause carbon monoxide to accumulate in the house. Major danger!

There are a few solutions for discouraging back drafting when your water heater is the last man standing. Your heating and cooling professionals will want to line your chimney when they upgrade your furnace. This reduces the inner size of the chimney and allows the water heater to create a better draft. You could also upgrade your water heater to a “power vent” model. A power-vented water heater mechanically creates draft in the chimney to avoid carbon monoxide buildup.

Heating and cooling professionals can help!

Air sealing, insulating and upgrading your heating and cooling equipment all save money, but they change your home’s environment. It’s very important to avoid the unintended consequences that can come about from tightening your thermal envelope.

At Boston Standard Plumbing and Heating, we can help you choose the most efficient heating and cooling options. We can also help you ensure that your home remains safe and comfortable, while also saving you money!

Call us at (617) 288-2911 to schedule an appointment today!

Photo Credit: David Singleton, via Flickr

Boston Furnace Replacement Considerations

The decision to replace a furnace can be difficult. If the decision to replace hasn’t already been made by circumstance, cost is the usually primary factor in the decision. Can you afford to replace your heating equipment, or can you get one more season out of the old furnace? Boston homes need heating equipment that can tolerate a tough winter, so what should you look at when considering replacement?

The cost of the replacement is certainly a consideration. Many homeowners choose to upgrade (or install) their central air conditioning unit at the same time they change out their heating equipment. While this isn’t strictly necessary, depending upon the type of heating system in the home, homeowners can save thousands of dollars by redoing the heating and cooling at the same time.

The cost of operation is also a consideration. For homeowners with oil furnaces, or oil-fed boilers, the cost of heating oil has risen sharply and steadily while the cost of other heating fuels has remained relatively constant. Heating oil is nearing $4 per gallon now, and this rise in price is stirring bad memories of 2008, when the price of heating oil (at times) was nearing a whopping $5 per gallon. Natural gas furnaces can heat the same space for about 2/3 the current cost of heating oil, and the cost of natural gas is expected to remain steady. (In fact, it’s dropped about 2% in the last 12 months.)

Electric heaters are also very cost-intensive, and because most electricity is produced from coal-fired plants, the carbon emissions related to electric heat make it one of the least green options for heating. You’ll pay about twice as much to heat a given space with electricity as you would spend on the natural gas needed to heat the same space. The cost of electricity is not likely to decrease sharply enough to make it cost-effective in the foreseeable future.

Aside from the cost of the equipment and the cost of operation, another consideration is safety. Very old furnaces (30+ years) normally have asbestos linings in or around the combustion chamber. These linings are considered safe as long as the asbestos doesn’t become “friable” or airborne. (Asbestos can also be found in some old ductwork.) Friable asbestos releases microscopic particles that can remain suspended in air. If asbestos particles are inhaled, they collect in the lungs and the body cannot clear them out. Long-term exposure to asbestos can lead to a particularly difficult form of lung cancer known as malignant mesothelioma.

The potential for health problems is real when the asbestos lining in a furnace deteriorates. New furnaces do not contain asbestos, so this kind of hazard would be mitigated by furnace replacement. In addition, very old furnaces are highly inefficient. By replacing the furnace, homeowners can recover the cost of the new heating equipment in just a couple of years!

An added consideration is that most high-efficiency furnaces vent directly to the outside, bypassing the chimney altogether. Exhaust gases from conventional gas furnaces and oil-burning heaters are vented up the chimney and can damage the interior of the stack over time. To repair this, the chimney may need to be rebuilt or lined, which can represent a significant expense.

In the next few weeks, I’ll look at oil-to-gas conversions, including reasons to convert, the benefits of direct venting for heating equipment, and the environmental considerations of oil heating. In the mean time, if you’d like more information about oil-to-gas conversions, or replacing old furnaces, please contact us at Boston Standard Plumbing & Heating at (617) 288-2911 for a consultation.