Heating systems that operate on cheap fuel are not always reliable and cannot be counted on as the only heating system in the house. Common examples are:
-- Solar energy and heat pumps: extended periods of cloudy weather mean you simply won't have enough heat.
-- Wood or Coal burning furnaces, stove, or fireplaces: If you aren't there to feed them they eventually quit heating.
-- Portable kerosene or propane "local" heaters: they require surveillance and refueling, and are not even intended to heat the whole house.
You can effectively combine inexpensive but "unreliable" heating systems with a good-old reliable, but expensive furnace. The objective is to use the more expensive "back-up" system only when you have to. Different regions suggest different tandem systems, and the characteristics of your individual house may play a role (do you have a place for solar panels?). Up until the arrival of Gas in Nova Scotia, the provincial government actively encouraged wood as a heating source.
Here are some tips on Tandem Add-Ons:
-- One furnace can be put directly into tandem with another furnace (with caution in connecting the exhaust flues). The thermostat of the more expensive, reliable on should be set several degrees below the normal temperature for your house. It will only come on if the other, less expensive furnace is not providing enough heat.
-- It is standard procedure for new heat pump or solar installations in Canada to have electric resistance "back-up" heaters built into them, to operate when it gets too cold. This function can just as well be served by your old furnace at no capital cost. And outside of Quebec, just about any fuel is cheaper than electricity.
-- Even if the systems are not connected directly in tandem they can have the same effect if the thermostat of the more expensive one is lower than that of the cheaper one, or simply below the normal household temperature. A pot-belly stove can heat the house and keep the oil furnace shut down until the stove runs out of wood.
-- Local heaters can inexpensively keep a living room or a recreation room comfortable all evening while the central furnace, turned down for the night, keeps the rest of the house considerably cooler. In this case, the thermostat of the furnace must not be installed in the locally heated room or the rest of the house will get too cold.
-- If you live in an area where electricity is much cheaper than oil but your oil furnace is good for another 10 years, you can install an inexpensive electrical "plenum heater." This is an electrical resistance unit that is installed inside the warm-air plenum of the furnace system. The small electrical unit operates during the milder fall and spring, leaving the oil to kick in during cold spells. The electrical utility companies love this system because you consume more electricity in the mild season but not during the peak demand season. And the oil companies are happy because you didn't scrap that furnace. A major advantage of this system is that you don't need to upgrade your electrical entrance -- an expensive proposition if you wanted to go all electric. A major drawback is that you will eventually have to replace the oil furnace anyway. One house in Thunder Bay that received a good re-winterization job, a bit of passive solar heat, and continuous fan operation, uses only a 5kw heater -- the oil furnace doesn't kick in all winter long! Ten to 15 kw units are more standard.
Mifumo ya joto inayotumia mafuta ya bei nafuu sio ya kuaminika na haiwezi kutegemea kama mfumo pekee wa joto katika nyumba. Mifano ya kawaida ni: nishati ya jua na pampu za joto: vipindi vya muda mrefu vya hali ya hewa ya mawingu inamaanisha kwamba utakuwa na joto la kutosha. - Mbao au makaa ya mawe kuchoma oveni, jiko, au fireplaces: Kama wewe si huko kulisha yao wao hatimaye kuacha joto. - Vipuli vya petroli au propani vinavyoweza kubebwa "kwa mahali fulani": vinahitaji uangalizi na kujazwa mafuta, na havikusudiwi hata kupasha joto nyumba nzima. Unaweza kuchanganya kwa ufanisi mifumo ya joto isiyo ya bei ghali lakini "isiyo ya kuaminika" na tanuru ya zamani yenye kutegemeka, lakini ghali. Kusudi ni kutumia mfumo wa "kuhifadhi" wenye gharama kubwa zaidi wakati tu unapohitaji kufanya hivyo. Mifumo ya tandem inaweza kutegemea eneo lako, na kwa hivyo, kwa mfano, kuna uwezekano wa kuwa na paneli za jua. Hadi kuwasili kwa Gesi katika Nova Scotia, serikali ya mkoa kikamilifu kuhamasishwa mbao kama chanzo cha joto. Hapa ni baadhi ya vidokezo juu ya Tandem Add-Ons: -- moja tanuru inaweza kuwekwa moja kwa moja katika tandem na tanuru nyingine (na tahadhari katika kuunganisha flues kutolea nje). Thermostat ya gharama kubwa zaidi, kuaminika juu ya lazima kuweka digrii kadhaa chini ya joto la kawaida kwa ajili ya nyumba yako. Itakuwa tu juu kama nyingine, nafaka nafuu si kutoa joto ya kutosha. Ni utaratibu wa kawaida kwa pampu mpya ya joto au mitambo ya jua nchini Canada kuwa na umeme upinzani "back-up" heaters kujengwa ndani yao, kufanya kazi wakati inakuwa baridi sana. Kazi hii inaweza pia kutumika na tanuru yako ya zamani bila gharama ya mtaji. Nje ya Quebec, mafuta ya kawaida ni ya bei nafuu kuliko umeme. Hata kama mifumo si kushikamana moja kwa moja katika tandem wanaweza kuwa na athari sawa kama thermostat ya moja ghali zaidi ni chini ya kwamba ya moja nafuu, au tu chini ya joto la kawaida ya nyumbani. Jiko la moto la tumbo la jiko laweza kupasha nyumba joto na kuweka tanuru ya mafuta imefungwa hadi jiko liwe na kuni. Vifaa vya joto vya mahali hapo vinaweza kwa bei nafuu kuweka chumba cha kuishi au chumba cha burudani vizuri jioni nzima wakati tanuru ya kati, iliyozimwa usiku, inahifadhi sehemu nyingine ya nyumba kuwa baridi sana. Katika hali hii, thermostat ya tanuru haipaswi kuwekwa katika chumba cha joto la ndani au nyumba yote itakuwa baridi sana. Kama unaishi katika eneo ambapo umeme ni nafuu kuliko mafuta, lakini tanuri yako ya mafuta ni nzuri kwa miaka kumi, unaweza kufunga gharama nafuu umeme "plenum heater." Hii ni kitengo cha upinzani wa umeme ambayo imewekwa ndani ya plenum ya hewa ya joto ya mfumo wa tanuru. Kifaa hicho kidogo cha umeme hufanya kazi wakati wa majira ya kupumzika na majira ya kuchipua, na huacha mafuta yaende wakati wa baridi kali. Kampuni za umeme hupenda mfumo huu kwa sababu unatumia umeme zaidi katika msimu wa joto lakini si wakati wa msimu wa mahitaji ya kilele. Kampuni za mafuta zinafurahi kwa sababu haijafanya kazi. Faida kubwa ya mfumo huu ni kwamba huna haja ya kuboresha mlango wako wa umeme - pendekezo ghali kama unataka kwenda wote umeme. Ubaya mkubwa ni kwamba hatimaye utalazimika kubadilisha tanuru ya mafuta hata hivyo. Nyumba moja huko Thunder Bay ambayo ilipata kazi nzuri ya kuhifadhi majira ya baridi kali, joto la jua la kijuujuu, na uendeshaji wa fan ya kuendelea, hutumia joto la 5kw tu - tanuru ya mafuta haifanyi kazi wakati wote wa majira ya baridi kali! Kwa mfano, 10-15 kW ya umeme ni kiwango cha juu.