I'm Givin' Ye All I Got, Laddie!

Mr. Scott of Star Trek presided over a complex of systems on the Enterprise that covered basic power sourcing ("dilithium crystals"), intelligent distribution throughout the ship ("transferrrrin' all power to tha warp drive, sirr") and a certain amount of storage ("full emergency powerrr at your command, captain") for those special times when you need it. The Enterprise was a little like your house in its basic needs and not a lot like your house in its energy independence ("ye can have full power in a few hours, captain, when i've regenerated the crystals"). You will do well to know a few vital things about your house's systems, particularly those involving life support (no power? the tv's out? oh, no, aren't there batteries for that?).

We may need a few posts to cover the whole picture, but let's start with the heating system.

If you have a thermostat on the wall in every room, radiators with no pipes extending to the basement or through the wall, and a bunch of large breakers in your panel marked "heat," you probably have electric heat. Much like your stove and oven, electricity passes through wonderfully engineered resistance elements ("Calrod" is a good keyword if you're searching) to produce heat, which is distributed by fins around the element over which air is persuaded to pass by convection. Convection is that tendency of temperature differences to stir up currents in a fluid, and air qualifies. Your boiling soup on the stove also qualifies. Gentle currents of warm air rise from the electric heaters and warm your house. All heat is expensive, but electric heat is possibly the most expensive energy source, especially in New England where I live. Even when oil did its spectacular bid to replace gold in the world's heart in 2008, electric heat was still more expensive as a source than oil. But, I admit, oil came close.

You can turn off room thermostats if you have electric heat, but the basic efficiency/inefficiency of the system is designed in. So many kilowatt hours in, so much heat out (to be particular, 3413 btu per kwh). After that, the challenge is keeping your heat indoors where it can't harm the polar icecaps. So, the good news about electric heat is: nothing goes up the chimney, at least not your personal chimney. The bad news, sad to say, is: expensive per btu, and very difficult to back up with emergency power. It takes a very large generator to run electric heat during a power outage, and very few homeowners can afford that.

If your house has radiators, cast iron or sheet metal baseboard in shape, in which copper or steel pipes extend toward walls or basement, you have either steam or hot water heat. If you have one large pipe entering each radiator, and a little silvery dingus on the other end that hisses when the boiler is running, you have steam heat. Somewhere in your basement a boiler burns gas or oil, boils water just like a pot on your stove, and allows it to pass, under five or six pounds of pressure, through pipes to your radiators. The steam has a temperature of just above boiling point, maybe 215 degrees, and it quickly heats the metal radiators, which, like our electric radiators above, encourage convective air flow and warm the room. The steam radiators, because they reach a surface temperature of perhaps 180 degrees at times, also contribute a significant amount of radiant energy to the room. This is why it feels good to snuggle close to a steam radiator on a cold day. The energy is traveling through the air directly to your body; the convection currents of air don't warm you as quickly or as aggressively. Get too close, though, and you can get a first degree burn from a steam radiator, so be careful, and watch the kids. But also enjoy draping your wet socks over the thing and watching them dry, until your kids start asking if Stinkfoot died in your house and what are you going to do about it. Steam can be distributed through baseboard or old-fashioned "bellows" radiators, the tall pretty ones you find in old houses. You can turn individual radiators off, if they have a primary shutoff, so room zoning and balancing are possible with this system as well. The only bad news is that the system operates at the highest temperatures of any system other than the one our last President calls "nucular," and there are inefficiencies and wastes associated with those higher temperatures that mean more energy goes up the chimney, more gets lost in your basement, and you wait longer for your system to respond to the thermostat while it makes steam.

If you have baseboard or "bellows" radiators which show pipes going in one side and out the other, or pipes emerging from floors and going back down again, you have a hot water distribution system. Let's visit the basement for a minute and you'll see the difference.

Your boiler (boilers boil water, furnaces make warm air) may have a maze of large (2 inch or larger) pipes emerging from it and crisscrossing your basement, a vertical glass gauge showing water level in the boiler, and a mysterious druidic device called a low water cutoff, in case the boiler runs short of water. These are the signs of a steam system, and if your house is old, don't touch or whack or kiss or hug or scrape or even look at your pipes; they may have old asbestos insulation on them. If you think you have asbestos, leave a comment and I'll talk to you about it some more, or wait for a later post.

If your boiler has a system of smaller pipes (usually one inch or smaller) pipes going out to various corners of your basement, and if you have one or more motor-driven devices cut into the pipes near the boiler, you have a hot water distribution system, in which water is heated to about 18o degrees and sent swirling through pipes to warm the radiators and heat your house. The advantages of hot water over steam heat have mostly to do with the fact that it operates at lower temperatures. The motor-driven devices are circulator pumps, pushing hot water gently through the pipes and back to the boiler, losing heat to the pipes and fins and housings before coming home to be heated up and sent out again.

You may have an oil tank in your basement. If you do, your number two heating oil delivers about 140,000 btu per gallon, minus inefficiency losses like what goes up the chimney and what stays in the basement. A gallon of heating oil is roughly equivalent to 41 kilowatt hours of electric power. What do you pay for a kwh? What do you pay for a gallon of heating oil? There. I told you. At fifteen cents a kilowatt hour, a gallon of oil, minus its engineering losses (i estimate 20%), will have to cost almost five dollars to be as expensive as electric heat. There are other small factors to be considered, like easy zoning of rooms, but rough math is good enough to put you on the right road.

If you have a large alien internal organ mounted high in one corner of your basement, and a steel or bright yellow flexible line running to the boiler, your energy source is probably natural gas, or possibly LP gas, a synthetic fuel like natural gas but derived from crude oil just like heating oil. Natural gas yields about 1000 btu per cubic foot, so 140 cubic feet of natural gas is equal to one gallon of heating oil. You can consult your gas bill and do the math. Natural gas, depending upon where you live and how it's taxed, can be very near the same price as oil, and certainly less than electric power. LP gas is usually a bit more expensive than oil, but still less than electric power. Unless those huge whirligig thingies in your backyard are out there working for you and no one mentioned it when you moved in.

If your house has no radiators of any kind, but rather flat louvers from which warm or hot air blows into the rooms to warm you, you have either a furnace or a heat pump. The furnace will be powered by one of the energy sources mentioned above: electric, oil or gas. The heart of the distribution system will be a rather noisy blower somewhere in the house, either in the basement, attic or in a closet. Some condo owners will find them behind small ceiling hatches. You can usually adjust the louver/grilles to increase or decrease or shut off air flow to a room, so there's good news. But the snuggle factor just isn't there. you can pull up a chair and sit over a floor grille, but it's not as nice as a radiator. Sorry. The good news? Your furnace and distribution system operate at the lowest temperatures of any system i know, so those efficiencies are yours to keep.

If you have no furnace, no boiler, just a big contraption outside that runs summer and winter and sometimes ices up, you have a heat pump. I can't go deeply into the physics just now, but I will wax scientific in a future post if you request it. Freon gas is compressed, heated (forgive me, engineers, but this myth is a useful one), sent though pipes into the house, and allowed to release its heat into a coil, over which air is blown (Willis Carrier, pray for me) to produce warm air for the house. Steel and plastic pipes called ducts carry the warm air through the house and release it through grilles. If you have a heat pump, bear in mind that it is only able to function when outdoor temperatures are above about 35 degrees. When the weather is cold, you rely on electric heating elements in your equipment which warm the air and get the same job done, but at electric heat prices.

If you're still reading, thanks for pushing through a large body of details, not all of which apply to you. And here's the payoff. In each of the systems we've discussed, the design inefficiencies and energy costs are fixed, but the distribution system is not. You can find a way, even with hot water radiators, to reduce the output of the system in a particular room when you don't require higher temperatures in that space. Now don't go freezing your water pipes and telling the plumber I sent you. But within reason, you can take some control. Adjust that air grille, turn the valve on that big radiator, lower that room thermostat if it controls only that room. If you have hot water baseboard radiators, with no valves available. you can use painter's tape to partially close the convection slot in the top of the housing. You're not working magic, you're just reducing the energy available to a certain space if it's not needed. Make your kitchen the warmest room. Heat your bath up only when everyone's using it, morning or night. Allow your bedrooms to cool off a bit during the daytime. Use the thermostat(s) to lower the temperature of a room that isn't in use. Again, beware of practicalities like water pipes. But small moves can add up, and, here at the bottom of the page, with no one else around, let's be straight: small moves are the only ones available to most of us. We can't all afford to install solar panels, or wind turbines, or sexy stainless boilers; but we can all afford to do the small things, and they add up---- especially if we all do them together.