Gas Heat vs Reverse Cycle – Gas vs Electric Heat Review
The most important thing about your choice of gas heating vs electric heat is the comfortable warmth it delivers.
So, do you choose Reverse Cycle Heating (heat pump) or Gas Heat?
The Comfort Factor – Gas vs Electric Heat
Comfort plays a key role in gas vs electric heat and how satisfied you will be with your new heater.
When you sit near your heater, you want to feel warm, not cold.
Almost everyone agrees that gas heat feels more comfortable but new research now confirms the “Why?”
The Research on Gas vs Electric Heat
In its most recent comparative analysis of residential heating systems, research firm Newport Partners used sophisticated building modelling software to answer the question with real data.
“You hear a lot of buzz about heat pumps being uncomfortable in the winter season, especially when outdoor temperatures are cold,” says Mike Moore, a consulting engineer with Newport.
“We wanted to find a way to try and quantify it.”*
What Makes for Comfortable Heat?
Comfort is a very subjective measure, so quantifying it is difficult.
With convection gas heaters, the temperature of heated air being delivered can have both a positive psychological and physical effect on occupant comfort.
“If the air temperature being supplied is below your skin temperature, then you are going to have the perception of being cooled, especially when there is a flow of air across your body,” Moore says.
So for the study, Newport assumed that when supply air temperatures are at or below typical body temperature — around 37°C — many people feel cool and uncomfortable.
In other words, if the air flow temperature being supplied is at or below your skin temperature, then you are going to have the perception of being cooled when you really want to be warmed.
How Was it Measured
Newport’s next step was to quantify how often different heating systems would deliver that cooler, uncomfortable air flow.
Moore used two building energy simulation tools supported by the US Department of Energy (DOE) to find out.
In both mixed and cold climates, the air flow from the reverse cycle heaters feels cool about 60 percent of the time during the heating season.
Convection gas heaters, in contrast, provide an air flow consistently above the comfort threshold of 46°C.
The Problem with Heat Pumps
There is a difference in air flow temperature supplied by the two types of heaters.
This is caused by the different ways the two systems generate heat.
Heat pumps draw heat from the outdoor air.
As outdoor temperatures fall, there is less heat available to transfer to the indoor unit, so the air flow temperature falls.
Some heat pumps will eventually turn to electric resistance heating to raise the temperature.
But before this booster heat comes on, the air flow temperature remains cool and uncomfortable.
And when the booster is active, electric resistance heat uses much more power and is the most costly way to heat your home.
The Advantages of Gas vs Electric Heat
Gas heaters operate independently from outdoor conditions.
A convection gas heater is simply heating the indoor air with gas combustion.
It supplies a steady, consistent air flow temperature above the comfort threshold, regardless of outdoor temperatures.
Gas heaters also have the advantage of heating up a cold house faster.
If you come home or wake up to a cold home, you want to get warm as quickly as you can.
The same is true for both LPG and natural gas heaters for sale.
Virtually all gas heaters are available in both LPG and natural gas versions.
Rinnai, Paloma, Everdure and Braemar all make gas heater models for use with both gases.
Price Comparison of Gas vs Electric Heat
Gas heaters are typically less expensive to purchase and easier to install, especially if you already have gas at your home.
With less moving parts and no refrigerant re-gassing issues, the cost of maintaining gas heaters should also be less.
Gas heaters typically have a much longer life span, too.
Both types of heaters are energy efficient, especially compared to conventional electric heaters.
For example, many gas heaters are rated at 5.8 or 5.9 Stars out of a maximum possible 6 Star ratin
Gas vs Electric Heat – Which do I Choose?
So, in the gas vs electric heat debate, is gas heat really more comfortable than reverse cycle heat pumps systems?
The research says it’s true.
People feel warmer when the air flow produced by their heater is well above body temperature.
Gas heaters do this 100% of the time while the research shows that heat pumps only achieve this 40% of the time.
What Size Gas Heater Do I Need?
What to Consider
If you buy too small a heater, it will not be able to adequately heat the intended area.
Selecting a heater that is too large will cost you extra money and oversizing can be unsafe.
A number of things need to be considered when determining your heater sizing:
♦ The volume of the area to be heated including consideration of ceiling height.
♦ The climate zone that you live in.
♦ The physical features of your home including wall & ceiling insulation, window coverings and carpeting.
♦ The kW output of the gas heater, not to be confused with the gas Mj input.
Heating Area Volume & Climate Zone
The required kW output required is primarily dependent upon the area to be heater and the climate zone in which you live.
The following rough guide assumes your ceilings are no higher than 2.4M:
Very Cold Zone: 1kW output required for each 8.5m²
Cold Zone: 1 kW output required for each 10m²
Cool Zone: 1kW output required for each 13 m²
Mild Zone: 1kW output required for each 16m²
The indicated heating areas would be adjusted down by 5% for each of the following conditions: house built on pillars (non-slab), no carpets on floors, no drapes on windows or a ceiling height exceeding 2.4m.
Deduct an additional 10% if the area does not have ceiling insulation.
Please note that this is only a guide and individual home designs and situations may vary.
Gas Heater Sizing Example #1:
You live in the Cold Zone and you want to heat an area 5m X 10m, which equals 50m².
Because 1kW will heat 10m², you should need a heater with a 5kW output.
Gas Heater Sizing Example #2:
Same as the previous example but in this case your ceilings are over 2.4m and you have wood flooring instead of carpeting.
You would need to deduct 5% for each of these two items.
So, instead of 1 kW heating 10m², it would heat 9m² (10% total reduction).
This means you would need a heater with 5.6 kW of output (50 ÷ 9).
Use kW not MJ
Megajoules per Hour (MJ/hr) ratings on appliances actually indicate the gas consumption of the appliance, not the heat output.
It is often expressed as just MJ.
Kilowatt Hour (kWh or just kW) is how gas heater output is measured.
Energy Efficiency Matters – Star Ratings
So, remember to use kW as a comparison and not MJ.
The efficiency of the heater, in converting gas energy to heat, is a key factor.
For example, a 25MJ heater with a 5.8 Star rating has an output of 6.2kW.
A 25MJ heater with a 2.8 Star rating only has an output of 5.0kW.
As a result, in a Cold Zone climate, they would heat 62m² and 50m², respectively.
This means that the 5.8 Star heater will heat an area 24% larger while using the same amount of gas.
Please refer to the manufacturers’ specifications to determine the exact kW output for each heater you are considering.
Minimum Room Sizing
Some States specifiy the minimum room sizing (volume of room in M³) and minimum ventilation requirements for unflued heaters.
Minimum room sizing also varies between thermostatically controlled and manually controlled heaters.
Portable heaters should not be used in bedrooms, bathrooms or hallways.
All installations must comply with Australian Standard AS5601 – Gas Installations.
Your gas fitter will be able to guide you on many of these points.
Manufacturer Sizing Charts
To make it even easier, most manufacturers have sizing charts, for their heaters, based on climate zone maps.
Take the time to measure the area you wish to heat and use these charts and maps to get the correctly sized heater.
It is always wise to follow the manufacturers’ advice.
*Excerpts for this article are from “Gas heating is more comfortable — myth or fact?” an article by Jeffrey Lee on the Propane Education & Research Council web site.
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The information in this article is derived from various sources and is believed to be correct at the time of publication. However, the information may not be error free & may not be applicable in all circumstances.