propane.
Insulation is actually better than any heating system you could possess. it keeps your body heat in and the cold out. Learned this in a science class ;)
depends on the type of D-fuel, and the type of burner,most home heating oils are #2 most D-fuels have an additive, may smell to high heaven,
diesel fuel contains detergent, cetane improvers,lubrocity improvers, etc. home heating oil doesn't. most application are interchangable. truck stops commenly sell home heating oil because its cheaper. they also sell premium diesel which is supposed to be real diesel. that's why drivers buy howes, or power service and dope their fuel. dyed fuel is for off road use and does not have road tax collected on it #1 and #2 are viscosity ratings.
The most economical heating is gas. Many areas of the country have very low gas prices when compared to electric. Solar is also a good way to offer heating.
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Natural gas is THE most useful fuel there is. You can fuel vehicles with it, run home heating and cooking systems, use it in industry, generate electricity with it, and even make it into things.
"economical" has no comparative or superlative form. You would say "more economical" or "most economical."
The 2013 Toyota Tacoma 4x4 has a very high rating for being fuel efficient. Since fuel consumption is the biggest cost is running a 4x4 truck, this would make it very economical.
Most fuel for heating is from fossil fuels such as oil, coal, and natural gas.
There are many economical choices in home air conditioning available today. Whether tying in to an existing heating furnace using a split-system type of air conditioner, or if you are needing an entirely new packaged unit, many home air conditioners are more affordable than ever before. It is best to get several bids from multiple HVAC approved contractors, as this is the most econimical route.
Generally the home heating, or cooling in hot weather.
The kerosene is a lighter oil. I think you would get more BTUs out of the heating oil. Just make sure that you are using the right fuel for the furnace that you have. Most now days would take heating oil.