GREEN COLD N' HEAT
COSTS AND GHG EMISISONS
Analysis and comparing hybrid HVAC system
I'll be comparing the hybrid system to an Air source heat pump (electric) and a combustion furnace (natural gas) while considering multiple factors such as cost, GHG emissions as well as the general benefits and disadvantages of Hybrid HVAC.
GHG EMISSIONS
Hybrid gas systems produce very low greenhouse gas emissions compared to an all gas furnace or an electric system.(Sager, 2018) It's also efficient in terms of electricity use as it minimizes impact on peak electricity demands (AEC & Enbridge, 2018). Reducing greenhouse gas emissions while not consuming colossal amounts of electricity is very important to mitigate climate change and hybrid systems seem to offer that solution for the Canadian market.
Sager, J., NRCan/CanmetENERGY, & Ferguson, A. (2018, April). Opportunities for Hybrid systems. Government of Canada.
COST-EFFECTIVENESS
Based on estimates given by local companies, Hybrid HVAC systems cost approximately 20000$ for material and installation; not counting operational costs. Whereas a high efficiency gas furnace system costs only up to 6000$ (and is even eligible for credit rebates!). The initial high price of hybrid system will definitely be a barrier to homeowners looking to reduce costs and emissions; and will cause more people to gravitate towards ''high-efficiency'' gas furnaces. But even though hybrid HVAC is a relatively expensive system, compared to an all-electric system, it's the most cost-effective solution to considerably reduce greenhouse gas emissions. (Sager, 2019)
CONCLUSION - GENERAL EFFICIENCY
Electric heat pumps
The benefits and drawbacks of heating systems strongly depend on the province's energy costs. Gas furnace remain in Ontario the fuel of choice for residential heating systems. (Statistics Canada, 2017) In areas where electricity is cheaper, like in the province of Quebec, heat pumps are the best solution; but if we're looking to reduce GHG emissions it's better to consider how the electricity is sourced. Heat pumps have low maintenance, reduce carbon emissions, but they are more difficult to install and don't function well in cold weather. (Braun, 2010)
In the case of Ottawa where the majority of furnaces are gas sourced (ONS, 2019) we can see that not all home benefit from an electric solution, unless the homes were initially heated by oil furnaces or electric baseboards. In many regions such as Ontario, MB and BC switching from gas to electric saves GHGs but increases costs. In places such as AB, SK, and NS switching from gas to electric not only increases costs but GHGs as well since electricity in these provinces are generative mostly by coal and oil. (Sager, 2018). In the case of Ontario, it seems that for the next 20 years, all electric heating systems will remain more expensive than gas furnaces no matter carbon taxes or forecasts. But for individuals willing to make the switch and reduce emissions, many professionals recommend having solar panel to save on electricity costs.
Combustion furnace: natural gas
''Space heating in the residential sector in Canada accounts for 15% of GHG emissions. Over 35% or 5.1 million homes in Canada use low cost natural gas for heating and are in regions with higher cost, low GHG-emitting electrical grids.'' (Sager, 2019) While natural gas is a cleaner fuel than coal or petroleum, it still emits a large amount of carbon dioxide into the air in the form of both CO2 and methane. Therefore, gas furnaces still produce the largest amount of GHG emissions even if labelled ''high efficient'' (See chart comparison: 3.5t CO2/year). Because gas furnace use the cheapest fuel for heating they are more commonly used. Considering the millions of spaces being heated with natural gas, it's not difficult to wonder how much impact this has in terms of emissions produced, and why seeing change in this industry is essential.
Comparison of different types of systems
Hybrid Gas systems offer compromise to having gas or all electric. They produce low GHG emissions: 0.7t/y vs 3.5t for gas. They also don't consume too much electricity: 3,623W vs 12,808 for an electric heat pump.
Hybrid system: electric and gas
Hybrid systems overall balances heat pumps and furnaces in the amount of electricity used and GHG production (see comparison chart at the top). It's the best solution and compromise to reducing electricity cost and most importantly greenhouse gas emissions. (AEC & Enbridge, 2018). Hybrid HVAC systems seem to be the most cost-effective solution to reduce emissions in space heating and cooling. By efficiently switching between the 2 fuels, this system can work well in the coldest temperatures and be adjusted based on electricity peak costs. As mentioned before it will take time before hybrid HVAC systems get implemented in most ''natural-gas provinces'' (MB, ON, BC), but educating homeowners as well as providing the right incentives will allow us to get greener homes and spaces, and find solutions to mitigate and even adapt to climate change.