Building for Efficiency: Decarbonization Doesn’t Have to Break the Bank
The following is part three of our four-part series Building for Efficiency, examining a groundbreaking new report on cost and emissions in new construction. If you’re just joining us, see parts one and two.
America’s natural gas utilities have been and continue to be committed to being part of the solution on climate change. While the previous entries in this series examined both the cost benefits of natural gas appliances and the major reasons customers prefer high efficiency natural gas appliances, thus far we haven’t looked closely at another invaluable advantage natural gas appliances bring to the table – emissions reductions. In many parts of the country, high efficiency natural gas appliances aren’t just the most affordable option, they’re also frequently the lowest emissions option available.
Nationally, an advanced all-gas home with a condensing natural gas furnace can reduce fifteen-year emissions by 17% compared to the emissions from a typical all-electric household. Compared with an advanced all-electric home with a cold climate heat pump, the advanced natural gas household typically can equal or exceed emissions reductions while cutting lifetime costs by thousands of dollars.
How is this possible? Well, natural gas used directly in the home is generally quite a bit more efficient than converting it to electricity. For every 100 units of source energy, 92 make it through to the customer when delivered as natural gas. If converting to electricity however, losses in generation and electrical transmission mean that the customer only receives 38 units of energy for every 100 units of source energy – between a third and half as much as the natural gas customer.
Of course, that’s only the beginning. There are numerous ways natural gas home heating can be a winner on emissions reductions. Some of those ways actually involve electric heat pumps! Hybrid systems that utilize natural gas with electric heating appliances in tandem can further enhance these benefits, providing both lower emissions and greater cost savings. This is because the customer can purchase a lower cost heat pump that is smaller than their home would otherwise need and run it for much of the year. The natural gas furnace is then turned on when it’s cold enough that the heat pump would be either working overtime (causing it to consume much more energy than at more optimal temperatures) or simply unable to keep up with low temperatures outside.
There are many options available to us. Take a look at the chart below, which compares both the lifecycle costs of owning and operating various home heating options, and their respective greenhouse gas emissions.
The first thing you probably noticed is that electric resistance heating, despite low installation costs, quickly becomes the most expensive option due to increased energy bills – and that it has by far the highest emissions associated with it. There is, after all, a reason we’re not seeing very many electric resistance furnaces put in these days.
Looking further down the list, you’ll notice that a high efficiency electric heat pump is likely to be quite good at reducing emissions! However, the high installation cost keeps lifecycle costs roughly on par with, or only slightly above, the low efficiency heat pump. While the emissions on a high efficiency heat pump are low enough to be comparable to many natural gas appliances, a low efficiency heat pump remains the second highest emissions option.
Next, let’s compare the natural gas furnaces amongst themselves. A low efficiency natural gas furnace has the third highest emissions, but only costs a little less to install than a high efficiency natural gas furnace. That high efficiency natural gas furnace has emissions virtually identical to the most efficient electric heat pump, but at a much lower cost! To summarize our key takeaways today:
- Natural gas appliances are typically as good or better on emissions compared to electric heat pumps.
- Natural gas appliances can achieve a similar level of decarbonization at a dramatically lower lifecycle cost. These technologies are all common today. However, if you paid close attention to the graph above, you likely noticed a reference to incremental RNG costs, as well as the inclusion of a natural gas heat pump. Don’t worry, we haven’t forgotten to discuss this – in fact, they both will have a starring role in next week’s piece on the innovative natural gas technologies poised to make a dramatic impact on home heating. Stay tuned!