There’s no time like the Maritimes. With a combined population less than that of metro Vancouver, and a land mass smaller than any other province, Nova Scotia, New Brunswick, and Prince Edward Island are a relatively tiny part of Canada. Our colonial history has blessed us with three separate provincial governments, giving us three distinct energy systems.  We also enjoy a climactic variance: Halifax and Saint John feature mild coastal weather, while Fredericton freezes and/or bakes depending on the season. The differences in climate and energy pricing makes it somewhat difficult to easily compare home heating costs in our region.

I’ve constructed a model using Carrier’s Hourly Analysis Program (HAP) that allows us to roughly determine energy budgets in three different cities: Fredericton, NB, Charlottetown, PE, and Halifax, NS. The model uses an identical house constructed to Efficiency New Brunswick’s guidelines for new construction. The home, an 1125 sq ft bungalow with an insulated basement, allows us to compare energy prices on an apples-to-apples basis.

The model home is heated with either an electric furnace, a natural gas furnace (with a nominal 90% efficiency), or an oil furnace (with a nominal 85% efficiency). I used prices from Heritage Gas and NS Power for Halifax, Enbridge and NB Power for Fredericton, and Maritime Electric for Charlottetown. No natural gas is available on PEI.  I also used a standard price of oil of $1.074/L. The HST for each province (13% for NB and PE, 15% for NS) is also applied, but the NS HST rebate is not discounted.

A nominal amount of household electricity use is applied for each city. This allows the customer, or meter, charge for each utility to be considered in a relative fashion. Hot water use is not modeled, although the nominal electricity use is large enough to account for electric hot water heaters in each simulation. Air-conditioning in summer is not considered in this model, although the model house does contain a 70% efficient heat recovery ventilator (HRV) as required by Efficiency NB.

We should first look at the climactic difference between each province. When we simulate the heating loads for each city, the results are:

• Halifax: 54.9 GJ
• Charlottetown: 66.4 GJ
• Fredericton: 69.8 GJ

This is the amount of energy needed to heat these homes on a yearly basis. Halifax, features a milder winter and thus requires less heating energy. The modeling program uses these values, plus a nominal annual consumption of 16,500 kWh of additional electricity, to determine the annual energy budget for each location. The model also applies the various regional utility rates to each city.

• Halifax (Gas Furnace): $4250
• Halifax (Electric Furnace): $5200
• Halifax (Oil Furnace): $5000

• Fredericton (Gas Furnace): $4000
• Fredericton (Electric Furnace): $4250
• Fredericton (Oil Furnace): $4850

• Charlottetown (Electric Furnace): $4650
• Charlottetown (Oil Furnace): $5250

While Fredericton has the highest energy load, the gas heating budget is the lowest estimate in the region. The opposite is true for electric heat in Halifax: the mildest winter gives us very nearly the most expensive form of heat. The relatively high cost of electricity in Halifax makes it the only locale where oil heat is cheaper than electricity.

To see just how expensive electricity is in Nova Scotia, I modeled each regional electricity rate in a Fredericton home (with HST adjusted to NB’s 13%).

• Fredericton (Electric Furnace w/ NB Power rate): $4250
• Fredericton (Electric Furnace w/ Maritime Electric rate): $4750
• Fredericton (Electric Furnace w/ NS Power rate): $5750

If NB Power adjusted its rates overnight to match those of NS Power, energy budgets would increase by almost 36%. Ouch.

These numbers should not be considered gospel. Energy modeling programs use simulation data for each city that allows the program to consider an “average” winter. The model also assumes that thermostats are not touched for an entire year, something that proves impossible in any home.  The numbers above do allow us to compare energy prices on an apples-to-apples basis in each city, and to consider how a city’s location affects heating costs.

Heat pumps are commonly cited as the most cost-efficient way to heat a home. In certain cases this is true, a properly designed system can provide a very comfortable indoor environment while using less energy than other types of heating such as natural gas or baseboard electric. While the machines are by their very nature efficient, an improperly designed or installed system can provide headaches and grief for a homeowner. This primer will explain some heat pump basics before we delve deeper into more complex heat pump systems in future columns.

Heat pumps operate using a refrigeration cycle, similar to a refrigerator or an air-conditioner. The heat pump compresses refrigerant into a hot gas. This hot gas is passed through a coil where it loses heat to the ambient space. As it loses heat, the gas condenses into a warm liquid. The coil where this takes place is called the condenser. The warm liquid exiting the condenser then moves through a valve that causes rapid loss of pressure. This valve is called an expansion valve. The refrigerant also cools significantly while losing pressure. The now-cold refrigerant enters another coil termed the evaporator, where it heat and boils into a cool gas. The cool gas enters the compressor, and the cycle repeats. This is a basic refrigeration cycle.

Heat pumps use the refrigeration cycle to transport heat from either the air or the ground outside your house into your home. Heat pumps that absorb heat from outside air are called “air-source heat pumps”. Central air-source heat pumps use condensing units located outside to absorb heat into refrigerant. Two pipes connect the condensing unit to an evaporator coil inside a furnace where the hot refrigerant heat air that is then used to heat the home. A ductless mini-split, also an air-source system, eliminates the need for the furnace coil, and delivers heat directly to the room in which it is installed.

Another form of heat pump is the “water-source heat pump”, also known as a ground-source or geothermal heat pump. These types of system circulate water through pipes in the ground, in a well, or even a lake or river. The refrigerant in this case absorbs heat from the water and delivers it to a coil in a furnace in a similar manner to the central air-source heat pump.

The heat absorbed from the air or ground outside your home isn’t free. The refrigeration cycle requires a compressor to operate. These compressors use electric motors to compress the refrigerant gas. A heat pump will use a certain amount of electricity to produce a given amount of heat. We call this ratio of heat energy to electric energy the coefficient of performance, or COP. If a heat pump has a COP of 3.0, it can produce 3.0 kWh of heat per 1.0 kWh of electricity. A heat pump with a lower COP will produce less heat per kWh, while a heat pump with a high COP produces more heat.

The COP will vary with the temperature of the air or ground. Soil and groundwater temperatures do not vary as much as air temperature. This provides a ground-source heat pump with a relatively constant COP. An air-source heat pump is expected to provide heat at outside temperatures ranging from –15°C to 15°C. When the air temperature is much lower, the compressors are required to provide much higher pressure refrigerant to produce sufficient heat. As the compressors work harder, they consume more electricity. Therefore, as temperatures drop, so will an air-source heat pump’s COP.

There will come a point where the compressors in a heat pump can no longer keep up with plunging temperatures. The unit then will lock-up and cease operation. This can occur at temperatures as high as 0°C or as low as -20°C. Modern residential units tend to lock out around -15°C. People still tend to prefer having heat inside when temperatures outside drop this low, so back-up heat must be provided. This is usually accomplished with an electric coil located in the furnace, or even with baseboard heaters throughout the home.

Ground-source heat pumps are generally considered more energy efficient than air-source heat pumps. They tend to have higher COPs, and are not forced to rely on backup electric heat when temperatures plunge. The major drawback of a geothermal style system is the initial cost. The cost of burying pipes in large trenches or deep wells greatly exceeds the cost of placing an air-source condensing unit on a 4 foot square concrete pad outside your home. There will come a point using a geothermal system where your energy savings will exceed the initial cost. If you plan on being in a home on a medium-to-long term time frame, the ground-source heat pump will save more money over the lifetime of the system than an air-source system.

There are many other factors that influence heat pump operation and efficiency. Multi-storey homes must have heat pump systems designed carefully to avoid over-heating or over-cooling certain areas of the house. Installing too large or too small a heat pump system can erode energy efficiency and shorten the life of a system. These pitfalls aside, heat pumps can provide significant savings over standard types of residential heat.

There are many different ways to heat your home in New Brunswick: oil, electricity, natural gas, wood, propane, &c. Each fuel has its benefits and its drawbacks, but the easiest way to compare fuel is by cost. I’ll occasionally be comparing the various costs of heating fuel in New Brunswick and the other Maritime provinces. Some heating sources, like electricity, have a very static price. Others, like natural gas or oil, can change weekly.

It’s helpful to read my previous post on the natural gas pricing structure in New Brunswick, as well as my description of the units of measurement used in this pricing comparison.

The following list compares only the marginal cost of fuel. It does not include monthly meter charges or HST. It does include, for combustion appliances, nominal efficiencies. Prices are current as of 7 November 2011.

Wood Pellets: $19.84/GJ (at $4.99 per 40 lb bag)

Wood: $20.00/GJ (at $250/cord)

Natural Gas (SGSRE): $21.77/GJ (at $10.5087/GJ delivery + $8/GJ gas)

Natural Gas (SGSRO): $24.51/GJ (at $12.8347/GJ delivery + $8/GJ gas)

Electricity: $27.36/GJ (at 9.85c/kWh)

Fuel Oil: $33.26/GJ (at 117.5 c/L)

Propane:$47.08/GJ (at 115.8 c/L)

Energy is measured in joules (J) in the metric system. A joule is a very small amount of energy. When discussing building heating, we’re usually dealing with millions and billions of joules of energy per month. Rather than talking about consuming 9,800,000,000 joules of heat per month, we say 9.8 gigajoules (GJ), where a gigajoule is equal to a billion joules.

In the Imperial system, we measure energy with the British Thermal Unit (BTU). A BTU is roughly equal to 1055 joules. Its easy to visualize a BTU when you consider the traditional definition: a BTU is the amount of heat necessary to raise the temperature of one pound of water by one degree Fahrenheit.

The problem when comparing energy prices is that various forms of energy are sold in various forms of measurement. Heating oil is sold by the litre, while electricity is sold by the kilowatt-hour (kWh). You’d have a very hard time buying a GJ of stove-cut wood, or a 40 lb. bag of natural gas. To ensure we’re comparing apples to apples, it’s beneficial to pick a consistent unit of measurement. For our intents and purposes, we’ll compare heating prices by the GJ.

There are two classes of residential natural gas customers: those who switched from oil, and those who did not. Enbridge aims to provide 20% savings to customers who switch to natural gas. Given the spread between oil and electric heating, Enbridge provides a similar spread for natural gas by imposing two residential customer classes: Small General Service Residential Electrical (SGSRE) and Small General Service Residential Oil (SGSRO). If you used to heat with oil, you’re charged the SGSRO rate, otherwise you are charged the SGSRE rate.

Natural gas bills are split into two portions: delivery charge and commodity charge. The commodity charge is the actual cost of the gas you’re burning, while the delivery charge is the cost of delivering that gas from a bulk pipeline to your home. Think of it as a pizza delivery: the pizza may cost $9.99, but it costs another $3.50 to deliver it to your house. Your overall bill is $13.49. Some pizzerias may not charge delivery, but you can be sure that cost is hidden in the overall pizza price. NB Power does not tell you that you’re paying a delivery charge for your energy, they just include it in the overall price. Enbridge breaks these two costs out.

I’m commonly asked about various forms of home heating. In our climate home heating is essential. There are a variety of ways to heat a home, and all forms will do the trick, albeit some will heat a home cheaper than the next. The following are the basic forms of heat commonly found in our province. I’ll discuss each form in depth on separate blog posts, but the following primer should help explain a few terms.

Forced Air 

This is one of the more familiar types of heating in our province. A furnace blows heated air through a network of ducts to registers throughout the house. One or two large return grilles allow air to return to the furnace. Furnaces can be heated by electric coils, natural gas, propane, fuel oil, wood pellets, or refrigerant coils heated by heat pumps.

A benefit to furnaces is that they actively filter the air in your home. The return air to the furnace is passed through an air filter that traps pollen, dust, dirt, and other particles in the air. Filters range in efficiency from a throw-away filter that will be found in most homes to more elaborate electro-static and high efficiency filters. Replacing your filters on a seasonal basis ensures the air in your home remains as clean as possible. Clean filters also allow the furnace to consume less energy to operate the fan.

Furnaces can usually be very easily equipped with air-conditioning coils. A refrigerant coil is added to the furnace and is connected to a condensing unit outside. This same condensing unit may be a heat pump unit that can heat your home in colder months. Not all air-conditioners can be used as heat pumps, but it is generally not that much more expensive to upgrade to a heat pump model. Most heat pumps today are air-source heat pumps. Geothermal heat is a type of heat pump system that provides heating and cooling to furnace systems. Air-source heat pumps draw heat from outside air while geothermal systems draw heat from the ground.

Hot Water Radiation 

Another type of heat that can be used is hot water radiation. A boiler heats water up to temperatures typically around 160°F to 180°F (for comparison, your hot water tank heats water up to 140°F, while water boils at 212°F). The water is pumped by a circulating pump to terminal units around the house. Terminal units can either be baseboard radiators, vertical panel radiators, fan coils that blow hot air, or even the old-fashioned but very handsome cast iron radiators. These units heat up and radiate heat to the room, hence the term radiator.

Boilers can be heated using the same types of fuels as furnaces. Certain types of fuels, such as natural gas, allow for more elaborate and efficient heating designs. Very advanced natural gas boilers that operate at 95% efficiency (compared to the 80% or lower efficient boilers in most homes) have been on the market for a few years in North America. Wood-pellet residential boilers are very popular in Europe and are beginning to be used in larger buildings in New Brunswick.

Despite the misleading name, hot water boilers don’t boil water. Steam boilers are found in very large buildings or building networks like hospitals or university campuses. Steam heat was once common in homes, but was phased out decades ago. Steam heat is a fickle and unforgiving science best left to well-trained stationary engineers.

In-floor Radiant 

In-floor heat is a type of radiant heat. Pipes embedded in concrete or stapled to the underside of floors distribute hot water through the floor assembly. The floor assembly is heated and begins radiating heat to the room. This is a very comfortable type of heat, especially beloved by pets looking for a warm place to lie down, or a wet person stepping out of a shower onto a warmed floor.

Radiant in-floor heat is not able to rapidly respond to a heat demand. If you come home to a cold house, it will take the floor a long time to warm up and begin distributing heat to the room. Conversely, it will take the floor a long time to cool down when heat is no longer required. This relatively long pick-up time means that radiant floor systems are not suitable for night setback, where thermostats allow temperatures in the house to drop while you sleep or are otherwise not in the home.

 Stoves

When your province seems to be 110% forest, you can be sure that people will have a wood stove in their basement or at the camp. Stoves and fireplaces contain wood fires that radiate heat into the surrounding space. More elaborate systems contain fans that distribute hot air into the room. Wood fuel has traditionally been split wood logs, but pellets are gaining an increasing share of the market.

A major benefit to wood heat is that it does not require electricity to operate. Unlike a furnace or a boiler, a wood stove will provide heat through a power outage. Wood fuel is also relatively cheap, especially if you cut it or split it yourself. A drawback to wood is controllability. Furnaces and boilers are controlled by thermostats that will set the interior temperature within a few degrees, while a traditional wood stove is much more variable.

 Electric Baseboard

We come finally to one of the most popular forms of heat in New Brunswick – electric baseboards. Electric baseboard heaters act very much like radiators in that they heat up and radiate heat to the room. They are very controllable and can be precisely set to any temperature needed. Baseboards allow zoning, which means each room can be set to an different temperature. They are also relatively cheap to install compared to other forms of heating described above. These electric baseboards sound pretty great, don’t they?

The major drawback is energy cost. Electricity is expensive, and competes with fuel oil as the most expensive form of heating in our area. New homes built in the province are sometimes provided both with baseboard heaters and mini-split type heat pumps to mitigate the cost of heating.

Your home encloses you from the elements. Not only does it keep you dry when it rains, it keeps you warm when it snows, and it keeps you safe in a storm. The inside of your house is your own personal eco-system. Before we can understand how to maintain this perfectly comfortable eco-system, we ought to discuss what protects us from Mother Nature – the building envelope.

The building envelope is a fancy way to describe the parts of your home that face the outdoors: walls, windows, foundations, doors, and roofs. Each item on this list helps encloses you from the whims of weather. These items all have specific properties and variances that affect how well they keep the heat in our out (depending on the season).

The building envelope physical property most people are familiar with is the “R-Value”. R-value is a unit of measurement that describes how well a physical material prevents the transmission of heat, a property known as thermal resistance. For our Canadian purposes, this generally refers to the ability of a wall to prevent heat from moving from our comfortable interior to the frozen exterior.

Heat will always flow from hot to cold (this forms the basis of the Second Law of Thermodynamics). Without delving too deeply into the physics of thermodynamics, the R-value tells us how many watts (or BTUs for those who are so inclined) of heat will flow through a wall of a given size with a given temperature difference on either side. More heat will escape when the temperature difference is higher (in winter, the difference across an outside wall can be as high as 50 degrees Celsius if it’s -30°C outside) or if the wall has a larger area (a 10’ x 10’ wall will transfer more heat than a 6’ by 8’ wall with a similar R-value). Our obvious goal is to reduce the amount of heat lost to the exterior; to quote my grandfather: “We’re not paying to heat the outdoors!”

We shouldn’t limit our discussion to walls; every part of the building envelope has an R-value. Part of the job of a HVAC consultant is to determine exactly how much heat a building will lose given the R-values of all the walls, doors, windows, foundation walls, and roof. It goes without saying that higher R-value building envelopes require less energy to heat than a building with lower R-values. However, there is another factor that affects indoor comfort, and that is infiltration.

Infiltration is air from outside your home that passes through the building envelope into the conditioned space. Older homes are sometimes called “drafty”, as they are less airtight than newer homes. Older homes were so drafty that there was no need for indoor ventilation given the amounts of outside air passing through the building envelope. This outside air must be heated to keep temperature constant in the home. As infiltration increases, so does your heating bill. In some buildings I review, infiltration can account for more of the heating load than windows, walls and roofs combined. Modern buildings have become much more airtight than their predecessors. Buildings became so airtight in the energy crises of the 1970s and 1980s that “sick building syndrome” became an issue. Buildings built today are provided with dedicated ventilation systems to ensure fresh air is circulated through the building without the cold drafts of yesteryear.

With this brief primer on building envelopes behind us, we can begin to discuss the real meat of this blog  – how to control the temperature inside our palace regardless of the season. My next post will describe the various ways we heat and cool our homes.

Congratulations, you’re a homeowner! You are the lord and/or lady of the manor. Along with all the social and financial benefits of home ownership, you’ve also become the climactic master of somewhere between ten and twenty thousand cubic feet of indoor space. Chances are that you’d like that space to be relatively comfortable, and if you’re like most other human beings, comfortable translates to a window of a few degrees on either side of 21°C (that’s 70 old school degrees).

You’d prefer that your indoor space remain this temperature regardless of outdoor conditions. You’d also likely prefer that the house be dry enough to prevent water from dripping down the walls, but humid enough that you don’t shock yourself on everything you touch. The ways you can meet your comfort desires, and how much you’ll pay to do so, are your introduction to the world of heating, ventilation, and air-conditioning, or HVAC.

HVAC is a topic that most people do not think about on a daily basis. We go about our days, traveling from our room-temperature homes to our climate controlled office in our air-conditioned cars. We’ll sometimes notice the baseboard heater or the register in the bedroom, or perhaps the boiler around which we’ve neatly piled boxes in the basement. We might even catch a glimpse of a room full of pipes and exotic equipment when we track down the maintenance man at school. HVAC is an industry whose goal is to be unnoticed.

I have been working in the HVAC industry for the better part of a decade. I entered the field directly out of engineering school, and have been designing commercial, industrial, and institutional HVAC systems since 2004. My professional career has focused on larger buildings, as it is generally not economically feasible for a homebuilder to hire an HVAC consultant. Residential systems are simpler versions of larger HVAC systems, but they are not without their complexity or diversity. My goal throughout this series of blog posts will be to educate both the reader and myself on the variety of options that exist in the residential HVAC market.

We have a plethora of HVAC options in New Brunswick. You can heat with electricity, natural gas, oil, or wood. Your options don’t end when you pick a heat source – for example, using electricity you can choose baseboard electric heat, an electric furnace, an electric boiler, or a heat pump. One natural gas boiler will not use as much gas as another to produce the same amount of heat. Some systems can be integrated with solar heat. Others can be adjusted to produce less heat when outside temperatures are warmer. I’ll explore all these topics, and more, as summer turns to fall, when a young man’s fancy lightly turns to thoughts of winter heat.