New Homes, why it’s not easy being green

New homes and homes upgraded for energy efficiency in cold climates are more likely to have mold and moisture problems than older ‘inefficient’ homes.  Building codes that have incorporated energy efficiency requirements may have done so at the expense of maintaining healthy indoor air, especially when so little is being done to educate home owners on how a modern home works.  If the installed ventilation systems in new homes are not used or maintained, air can get stale.  Stale air has higher humidity and possibly unhealthy or even hazardous gases and vapors, the result of people pets and plants breathing and exhaling water vapor and carbon monoxide, showering, bathing and cooking.  Small amounts of potentially cancer causing ground gases like Radon may be seeping in through basements with inadequate or unused ventilation, building materials, paints, adhesives, carpets, flooring, cabinets may off-gas various solvents or water vapor as they age, which could be removed by a good ventilation system, provided people use it.

In places where outdoor temperatures remain at or below -18 C, or zero Fahrenheit, like Edmonton, home energy efficiency means reducing heat loss.  Heat is lost from homes in two major ways, heat energy transfering from hot to cold through exposed walls, windows, doors and ceilings, and through the loss of heated air replaced by outside cold air that has to be heated.  A small amount of heat energy is also lost through radiation, but that is negligible.

A house in winter is a box full of hot air, if left it will cool, the same as the cup of Starbucks left sitting. As indoor air comes in contact with walls, windows, etc., heat moves from the warm air to the cold surfaces.  Exterior walls windows and doors in turn pass the heat to outdoor air.  Left long enough all the indoor air and all surfaces in contact with it will reach the same temperature, whatever it is outside, (which is warmed infinitesimally, but not so the squirrels would notice).  The rate of cooling can be slowed by insulation the same as a not so green foam coffee cup.

Insulation in homes is mostly fiberglass batts, a type of fiberglass blanket installed between the studs, (the 2by sticks that make up exterior walls), and loose fiberglass blown into the attic.  Fiberglass is very thin strands of glass. Put your hand on a window when it is cold out, glass is not a very good insulator, the actual insulation is provided by trapped air, which is a very good insulator, the fiberglass just keeps the air from moving (the same is true for that foam cup, trapped air is actually doing the insulation).  Fiberglass and its cousins, mineral wool, cellulose, wood chips etc., have a insulation rating of about R3.5 per inch, (excuse the imperial measurement, but that is what most people are familiar with).  So, an ordinary house with 2X4 walls will have walls that are approximately R12, and if they have about 12 inches (300 mm ) of attic insulation, for a ceiling rated at R40.  With the exception of the R40 attic insulation, it is also pretty much the way we have been insulating homes in Alberta for 100 years.

New homes have different attics than older homes.  Older homes made roofs and attics using rafters and joists, 2by lumber that had to sized deeper for the loads it was expected to carry, a typical joist depth (the lumber the ceiling was fastened to) was 6 inches (150 mm), filled with wood chips for an R rating of about 19.

New homes are built with trusses instead of rafters and joists.  Trusses are engineer designed triangles of thin lumber, like those toothpick bridges they made you build in elementary school.  All those triangles make access to attics difficult, storing stuff is no longer an option, but otherwise useless attics are easy and tempting to pack with insulation.

So insulation wise, a new home does not necessarily have much more insulation in the walls than great granny’s Edmonton* 1920 new house had, but do have more attic insulation over the top floor ceiling.   This is all good, great granny’s builder was no dummy, he knew how to build a house for an Edmonton winter, but don’t automatically assume that today’s new home construction is advanced as say, the way today’s new cars are made over  cars made 100 years ago.

A dirty little secret is that home builders don’t like to spend money on stuff that can’t be seen, because Mr. or Ms. Newhomebuyer aren’t eager to hand over more money on stuff they can’t see.  It is usually easier for a new home sales person to convince buyers to upgrade to granite counter tops than triple glazed windows and energy efficient ventilation.  Another dirty little secret is that even though attic insulation has gone from R19 in 1920 to R40 in 2016, that does not make much difference in heat loss, but it does sound good.

A ceiling is a horizontal wall with no windows or doors.  Heat loss happens over exposed cold surfaces, a function of area, consider a 2000 square foot two story square house, each story 9 feet high, and four outside walls 31 feet wide, total exposed wall area is 31 X 9 X 4 X 2 stories, or 2200 square feet of exposed no better than R12 wall vs 31 X 31, 1000 square feet of ceiling exposed not quite to the exterior, but to an unheated attic that still has a roof to provide a bit of weather protection.

Windows and doors have much lower R ratings, no better than R 3 for triple glazed windows, not quite R2 for double glazed or Great Granny’s double storm windows that had to be taken down and stored in the spring.  Windows, old or new provide a fraction of the insulation provided by an ordinary insulated 2X4 wall with siding.  A new home probably has more window area than Great Granny’s as well so that 2200 square feet of wall will add up to a lot less than R12 overall when windows and door area is factored in.   So, by all means insulate the heck out of the attic, but don’t expect a great improvement in heat loss.

One thing that has changed a lot since Great Granny moved into her new home is dealing with the second major source of heat loss, air leakage.   Older homes could be pretty drafty, especially around windows and doors or any other openings such as electrical outlets in exposed walls and ceilings.  Air leaking out is replaced by unheated air leaking back in which will need to be heated.

Home builders have been dealing with air leakage for about 50 years, as plastic films used for air barriers became cheap and available.  Sealing and caulking openings, like windows and doors when they are installed or replaced is fairly easy to do, like stuffing the attic with more insulation. As building codes change, requirements for air sealing are tougher, enabling those who write codes to pat themselves on the back for being green and saving energy at no cost (to the code writers).

New homes are very tight, if built right, very little air can get in or out.  If you are thinking this is good stuff, ask any kid what happens when you put a living frog in a screw top jam jar with no air holes.    We need fresh air, our homes need fresh air, and as homes got tighter, things needed to be done to ensure that a home received fresh air.

The basic requirement as of this writing is a fresh air intake duct and mechanical ventilation (fans) to bring in the fresh and remove stale air.  The most common way Edmonton builders comply to ventilation code is to insert a fresh air intake into the forced air heating system return air duct, so that whenever the air handler (furnace) fan is running, fresh air is brought in by the furnace and distributed through the heating duct system.  A ventilation switch operates an exhaust fan and the furnace fan at the same time when it switched on.  Homes that do not have forced air heating need to have an exhaust and intake fan operated by the ventilation switch. An HRV (heat recovery ventilator) is a self contained unit that can take care of bringing air and exhausting stale air, with the added benefit of using exhausted air to warm incoming air with a heat exchanger.   The most basic systems are operated by a switch which require the occupants to decide whether or not they need fresh air.  More sophisticated systems use automated programmable controls to ensure that a home’s air is exchanged on a regular basis.  The Canadian Home and Mortgage Corporation (CMHC) recommends an indoor air change every 3 hours.

Most homes built before 2010 in Alberta had an ‘automated’ air exchange system operated by the chimney.  Most homes in Alberta are still heated by fire (just like those jolly old caves used our great great great… and on so great grannies).  For the last 70 years the fire has been natural gas burned in a furnace, previously  we burned coal, wood and before that, flaming dried buffalo poop kept tipis nice and toasty.

A fire requires air to burn, it also produces smoke if you are burning coal, wood or buffalo droppings, but even clean burning natural gas produces water vapor and carbon dioxide, which has to be gotten rid of.  A chimney or an opening up high allows the hot products of combustion we don’t want to naturally rise up and out, carrying warm air with it, which was replaced by incoming cold air, leaking in from everywhere at first, and for the last few decades by combustion air intake ducts. By placing the furnace, chimney, and combustion air duct in the same room, usually the basement or part of it, the incoming combustion air also mixed with the air in the house, and indoor heated air went up the chimney.

The drive to save energy and make homes and appliances more efficient resulted in redesigned for energy efficiency furnaces that use no inside air, Today’s high efficiency gas furnace, the only kind available, draws all of its air for combustion from outdoors, extracts most of the heat from the exhaust before blowing it back outside through a plastic vent pipe at the side of the house instead of a chimney, so no more heated air flying out chimneys and no more automated ventilation.

New homes have an adequate ventilation systems, provided people use them.  You may be saving a few pennies on your gas bill by keeping fresh air out of your house, but the possible health costs or damage to your home will give a 21st Century meaning to the phrase penny wise, pound foolish.  It is fairly easy to keep indoor air fresh, use the systems that are installed in your home, make sure that the air intakes are free to draw in the kind of air you would prefer to breathe, and make a practice of  opening doors and windows every so often to let some fresh air in.

*Not necessarily true for regions that did not experience extremely cold winter temperatures.

Blown in fiberglass insulation

Most new houses in Edmonton insulate the attic with blown in fiberglass, a light fluffy insulation not too dissimilar from the poplar fluff that will blankets our streets and yards in early summer.  In some instances, when inspecting new homes I have found that the blown in fiberglass can be blown around inside the attic, creating insulation voids.

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Wet spot on ceiling

The wet spot on this ceiling occurred the morning after a late night thunderstorm with high winds and blowing rain.

nobaffles1
Insulation baffle is missing

The insulators forgot to install one of the cardboard baffles fitted between the trusses.  The baffle allows air to move from the eaves to the underside of the roof sheathing, essential for good attic and roof ventilation while holding the insulation in place.  The high winds blew the insulation off the soffits and also allowed water to enter the roof and collect on the ceiling where it leaked through the vapor barrier and created a wet spot on the ceiling.

Insulation voids on ceiling
Insulation voids on ceiling

In this new home the thermograph indicated there was little or no insulation in various spots on the ceiling. The inspection revealed that parts of the attic were bare, and insulation piled up in fiberglass drifts in other spots.

Insulation has been blown completely out of the truss space.
Insulation has been blown completely out of the truss space.

Talking to the builder revealed that the insulation had been installed before the soffits were covered, a wind storm had blown the insulation from one end of the roof to the other.

In the next picture, in this newly built home the roofers mistakenly installed an extra gooseneck ventilator for a bathroom exhaust.

An extra (unneeded) gooseneck is allowing the wind to blow the insulation underneath the opening.
An extra (unneeded) gooseneck is allowing the wind to blow the insulation underneath the opening.

There was no exhaust required here, so the gooseneck was left open, allowing the wind to blow into the attic, dispersing the insulation underneath it.  A truss had been uncovered, if left, the wind would eventually blow away all the insulation underneath the gooseneck, exposing the ceiling.

Cooking with gas

cook with gas

Cooking with natural gas can be more than seven times cheaper than cooking on an electric range.

Natural gas is almost always used to make heat.  You probably have a natural gas furnace.  If you have natural gas available you can save a lot of money by also using natural gas to heat your water, dry your clothes and cook your food.  The more gas you use, the more you will save.  If you need more heat than your furnace is providing, consider natural gas space heaters or garage heaters.

Using natural gas does require more care, you should never leave a gas stove on if you are not in the house, gas appliances have to be installed by qualified people, and need to be properly vented to ensure that all products of combustion are safely disposed of and you will need carbon monoxide detectors.  A home inspection by your East Side licensed home inspector can tell if your appliances are properly installed.

How much cheaper? If you already have gas it is easy to compare by converting heat energy units to electrical energy units. Natural gas is sold by the cubic foot, cubic meter, or by the gigajoule.  A cubic foot of gas contains the same amount of energy as 0.293 kiloWatt hours of electricity, a cubic meter has energy equivalent to 10.35 kWh and and a gigajoule converts to 278 kWh of energy.

Using your gas bill for any month, divide the the quantity of gas you were billed for into the total gas bill.  Now you know how much it cost you to bring the gas into your home for that month.   For the same month do the same for your electricity bill, divide the number of kiloWatt hours into your total bill for the delivered cost of your electricity.

You will find that even though you were charged say, 10 cents a kiloWatt hour, your delivered cost was closer to 25 cents a kWh.  The gas company does the same thing, someone (that would be you) has to pay all the overheads for maintaining the wires, pipes, people and plants that bring energy to your home.  So now you know, say that your electricity for say January 2013 was 25 cents, and your gas cost was $9.00 a gigajoule.   Multiply 25 cents (1 Kwh) times 278, the number or kWh in 1 gigajoule, = 69.50 what the same amount of electricity would have cost you for the gas you used.  (number of cubic feet times 0.293  cubic meters times 10.35)

Do this calculation for a summer month and a winter month, the cost of gas delivered to your home is much higher in the summer because of the fixed costs part of your bill,  you may find that using gas is only twice as cheap in the summer.

If you are confused why less gas should cost more than more gas, think of it this way.  You need to get gas, as in gasoline, for your lawnmower.  The pump price of gasoline is, say, $1.00 a liter, so you get in your car and drive 5 kilometers to the nearest gas station, fill  your 5 liter container and pay the man 5 bucks.   But, you have driven a total 10 kilometers back and forth to get that gas, your car gets pretty fair mileage, 10 liters per 100 km, even so, that 5 liters has now cost you 6 bucks (1 liter to drive 10 km).  But wait, there’s more!  your car insurance is 365.00 a year (you wish), your car depreciated $3650 dollars this year, maintenance and tires add up to however many cents per kilometer they are,  lets say it cost you 25 cents a kilometer to drive your car, and your car also costs you 11 dollars a day whether you drive it or not.   So the trip to buy to 5 liters cost five bucks to fill the gas can, two fifty to get the gas home, and 11 bucks to have a car handy when you need it for getting a can of gas and other stuff.  So instead of using a tiny 5 liter container, buy a 25 liter container, even though it costs five times as much to fill, it saves you four trips,and ends up costing you less.

The same goes buying gas or electricity.  The people who supply you with gas and electricity, the pipes and wires, processing plants and generating facilities have to be there even if nobody is using at them at one particular moment, and all these costs plus whatever else they can gouge you for  and the profits, that as we all know, make the world go around, show up on your bill whether you are buying more gas or electricity or less.