Archive for the ‘Nova Scotia’ Category

De-mystifying heating systems

By now, I’m sure you’ve heard or seen numerous ads touting some miracle radiant heater or special pellet stove that will “slash your heating bill by 50%!”…or something similar. Lots of claims about how efficient the heating system is and how much money it will save you.

The plain truth is that how much money, and energy, any heating system will use is mostly dependent on the building itself and how efficient it is, or isn’t (see my previous post on the building envelope). Try putting your car heater on full blast with your windows down on a day like today (-30 wind chills) and you get the picture – it doesn’t matter how much heat the system puts out if you can’t keep the heat in.

For the purposes of this discussion, let’s assume we start with building you a very efficient home. The choice of heating system could be oil, natural gas, wood/pellet, electric, solar-assisted, air-source heat pump or geothermal heat pump, or perhaps a combination. In all cases, passive-solar design features should be incorporated into the house as much as possible to harvest this free heat. We’ll also assume you’re building a house that is, say, 2500-3000sf in total (if we’re truly searching for efficiencies, smaller homes should be considered).

Let’s dispense with oil right out of the gate. Personally, I won’t install it in a home; it has too much environmental disaster potential (anyone remember a recent tank leaking a large amount of oil into a Bedford lake??) and if you’re watching global prices, it’s likely to become extremely expensive in the coming years. Plus, the CO2 emissions from extracting, processing, transporting and burning the oil are huge. Natural gas is far cleaner than oil, is more efficient and does not require a tank. It is, however, still a petroleum product that has to be extracted, processed and shipped to be burned…and is limited in its availability.

Wood and wood pellets are less common as a main heating system, however can be used in a main furnace in conjunction with the forced-air circulation system that is now required in all new construction. There’s a lot more work involved in splitting (if you choose to), stacking, storing, moving and cleaning up after the wood (or pellets)…and you have to be there every day to keep the furnace stoked, but for those who prefer to do that, and have access to the wood (it is a renewable resource), then it can be a viable option.

Electric heat, via a boiler for radiant heat or from baseboards, was commonly used in the past, however is waning in use due to its percieved costs and the fact that if it is your main heat source, you no longer qualify for most of the rebate programs out there for efficient housing. Even though we have an ongoing shift to increased renewable electricity in Nova Scotia, I still agree that electricity should not be the primary heat source.

All of the above sources suffer from one common drawback. They cannot ever achieve above 100% efficiency, and by that I mean produce more than 1 unit of energy for every unit of energy you feed into the system. You may get as high as 90-95% at best, yet it is still always more energy in than out. Remember that every system is still drawing electric power to run fans, burners and any associated equipment…and the fossil fuels (with perhaps the exception of wood) caused more energy to be burned off getting to you from start to finish than they possess when you finally get to burn them. That part is scary.

That leaves us with what I believe to be the best options; solar, air-source heat pumps and geothermal heat pumps. Solar panels can be used for pre-heating domestic hot water, for pre-heating air, and for providing electricity. Relying on solar for most of your heat is possible with a very good design, building orientation and high-performance envelope. Be sure you have some expert advice as this is not for amateurs. The beauty of solar is that once you have the system in place, you’re not “buying” energy from any source to provide heat, so you can achieve more than 100% efficiency (you still need electricity to run fans, etc.). As long as the sun is there, the heat will be there.

Heat pumps have become very popular, and for good reason. Even though you need electricity to run the compressor and fans, it actually produces more energy that it uses – from 300% to as much as 520% efficiency, with the geothermal systems being on the higher end. Air source heat pumps provide both heating and cooling (you simply reverse the system to cool in summer – it works on the same principle as your refrigerator) so you get both features with one system – none of the other systems can do this. The real gem is the geothermal heat pump systems; they provide not only heating and cooling (at a higher efficiency than the air-source units), but also pre-heat your domestic hot water so less energy is needed to bring it up to the temperature you want at your taps and shower. Even better is that during summer with the system is in cooling mode, all the heat it extracts from the air inside the home gets transferred into the hot water pre-heat tank so that very little energy is needed to use the water at your taps/showers. It’s a real all-in-one system that has the free energy of the earth available 24/7 regardless of weather conditions, time of day or time of year.

Of course cost is a consideration. Of the systems I choose as the best, the air-source heat pump would be the lesser priced to install with the solar and geothermal systems being a bit more, though also deliver the best bang-for-the-buck in the long run. All are very efficient and you can’t really go wrong with any of them. Actually, let’s not use the term “cost” and call it “investment“, since that’s exactly what it is…an investment in your home that produces enormous savings in purchased energy. And that helps our communities stay cleaner as well as lower your costs and add significant value to your home. Ten years from now when someone is looking to buy a house, they will be looking most favourably at the ones that use the least energy. Want yours to be at the top of the list?

Remember that when you build a high-performance envelope around the house, and incorporate good design elements, your system really does not have to work very hard to keep you warm, or cool. So invest in good construction so that your operating costs are kept very low, and stable, and see both the savings grow over time as well as your re-sale value.

As always, please do provide your questions and comments.

Andrew W. Alcorn, CET
Innova Builders, Inc.

Andrew is a member of the Halifax Chamber of Commerce Energy Advisory Group
and the Canada Green Building Council (Atlantic Chapter) Residential Committee

The building envelope – The most important factor in energy savings

You hear it talked about – the “envelope” of your home. But what is it?

The envelope is comprised of the foundation walls, basement floor slab (or ground-level floor slab if no basement), exterior walls, windows and doors, and the top floor ceiling. These are the areas of living space that are exposed to outside air or the ground, and are the surfaces that leak heat, air and moisture either in, or out, of your home. Regardless of how “efficient” your heating system may be, if the envelope does not seal off air flow and insulate properly, you’re wasting huge amounts of energy, and money. On top of that, the comfort level of your home will be very difficult to control.

Newer homes are built with better air-sealing characteristics in order to meet building code standards, and are (usually) built with higher levels of insulation. Often, the airflow is not blocked from entering the wall cavities, but does get stopped at the back of the drywall against the plastic vapour barrier – this still causes much heat loss, even though air leakage into the interior of the house is kept to a minimum. Older homes tend to have poor insulation levels and even poorer air-sealing, giving them an even larger potential for energy savings.

Let’s start with what can be done with new construction. Opinions differ on what the “best” construction methods are, and there are several options for very efficient buildings, with varying price tags attached to them depending on just how far you want to take things. Whether you build to Passive House standards,  use ICFs, or my InnovaWall system, keeping outside air out of the envelope and having a high level of properly installed (and I can’t stress that part enough) insulation are critical to ensuring your house uses little energy to heat it. Passive solar features should always be incorporated as much as possible to utilize the free energy from the sun, basements should be insulated on the outside to allow the concrete to act as a heat sink, and the combination of all these features means your heating/cooling system needs to do very little to keep you warm or cool. Of course in all cases, a properly designed and balanced (again, cannot stress this enough) HVAC system with a high-efficiency heat-recovery ventilator is required to ensure fresh air circulation and comfort.

When it comes to existing homes, especially older ones, creating major energy, and comfort, savings requires some renovation work. We often see people replacing their windows, doors and siding all at once on an older home and this is a prime opportunity to upgrade the insulation and air-sealing of a large portion of the home`s envelope. By furring out the new siding a couple of inches, this creates a void that can be filled with closed-cell sprayfoam insulation which is extremely good at sealing air leaks and providing a significant insulating value, even in just a 2″ layer. I have seen many homes with rigid styrofoam insulation boards added at some point, yet the house is still cold. Why? – because they did not seal off airflow from getting under, around or behind it. Once you allow airflow by, you just wasted your money on that insulation.

Because it is such a great insulator, vapour barrier and air-seal, closed-cell sprayfoam is also ideal for those basements and ceilings you’re looking to upgrade the insulation on…just be sure you have taken care of any water leakage first.

These are the basics, and there are many details involved in complete installations, so please send along your questions or comments on this topic.

Andrew W. Alcorn, CET
Innova Builders

Andrew is a member of the Halifax Chamber of Commerce Energy Advisory Group
and the Canada Green Building Council (Atlantic Chapter) Residential Committee

The Greenwashing Effect

Green-wash (green’wash’, -wôsh’) – verb: the act of misleading consumers regarding the environmental practices of a company or the environmental benefits of a product or service (courtesy

Like many others, I’m getting tired of all the companies and agents jumping on the preverbial “green” bandwagon with misleading and downright bogus claims of energy efficiencies and being environmentally friendly.

They call what they are building or selling a “green home”, or that it “meets standards” or has some special “designation” they made up that is not recognized by any legitimate organization. They will use terms like “energy efficient materials” or “EnerGuide rated” or say the house is “recognized”. What they don’t tell you is what “standards” they mean, who recognizes them or what the EnerGuide rating actually is. I could have a barn EnerGuide rated – the rating would be awful, but it would be “rated”. And what are these “materials” and how, exactly, are they integrated into the building envelope where they are used in what system?

You’ll hear talk of how a house has an efficient heating system, perhaps using an ETS (Electric Thermal Storage) unit that uses off-peak cheaper electricity, or a heat pump or other systems. What you don’t often hear is details of how the house is actually built to take advantage of these systems and require a small-capacity unit. Simply having an expensive ETS unit or heat pump installed is no measure of a house’s efficiency and may only mean wasting cheaper electricity.

When you start asking pointed questions (as I did of one agent making all sorts of claims in a public ad) you get some really vague non-answers and a very obvious run-around on the subject. Many are misleading the public in the hopes of coercing people into buying their products.

Do your homework on how a house is made to be truly efficient (insulation systems, heating/cooling systems) and start asking questions of a builder or selling agent. If they can’t give you specific answers that line up with your research, then you may need to think twice about what you are considering buying. Your home is a huge investment and in today’s environment, with the available technology and products, there is no excuse for a new home to be an energy-waster. We cannot afford it.

Andrew W. Alcorn, CET

Innova Builders, Inc.

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