Energy efficiency in the home has been a popular topic for many years. Home appliances, HVAC systems, energy-saving windows, and even LED light bulbs are all promising to save energy and cut costs.
But did you know that an energy-efficient roof is one of your best resources for saving energy? An energy-efficient roof can save you hundreds of dollars every year.
Let’s examine energy-efficient roofs and how your roof can help you lower your energy bill and keep you more comfortable in the process.
- What makes a roof energy efficient?
- Do energy-efficient roofs really save you money?
- What type of roof is the most energy efficient?
- Are they more expensive?
- What are the pros and cons? Is there a difference between an energy-efficient roof and a “cool roof”?
- Is there a difference between energy-efficient and cool roofs?
What Makes a Roof Energy Efficient?
According to GreenBuildingAlliance.org, 90% of roofs in the United States are poorly designed and built with dark, non-reflective materials that absorb rather than reflect heat.
Rooftop temperatures can get 90 to 100 degrees hotter than the outside air temperature. With a dark, heat-absorbing roof, this heat transfers into your attic and, ultimately, your home.
While good insulation offers some relief, it doesn’t stop the transference of heat from the roof top to the attic. And when your attic is overheated, that excess heat will transfer into your home and make the A/C work harder than it should.
Two factors impact a roof’s ability to stop this transference of heat: solar reflectance and ventilation.
Solar Reflectance Index
The Solar Reflectance Index measures a roof’s ability to reject solar heat (solar reflectance) and release any heat that is absorbed (thermal emissivity).
The higher the SRI number the better.
Lawrence Berkeley National Laboratory found that raising the SRI from 25 to just 40 can lower the surface temperature of your roof by more than 13 degrees. That could translate to a 15–20% savings on your energy bill.
Lighter colors reflect heat better than darker colors, and certain coatings can add even more reflectivity. But the key to an energy-efficient roof is that it will reflect the sun’s radiation away from the house.
That means less heat gets transferred to the attic. And a cooler attic means less heat gets transferred to your home.
Solar reflectance might not seem as important in colder climates, but even if you live where summers are short, the savings can add up.
Another factor for keeping your roof cool is ventilation.
Good ventilation keeps any heat that’s transferred to the attic from building up. If the temperature outside is in the 90’s, attic temperatures can get as high as 160 degrees.
And that heat has to go somewhere.
Without proper ventilation, it will transfer to the inside of your home. And if temperatures get too extreme, it won’t just raise your electric bill — it can actually damage your roof.
Static vents, wind powered vents and eclectic vents are the three main types of roof vents used in residential roofing. Each has its pros and cons.
Which vents you choose, and how much ventilation you need, is a question your service roofer can answer more precisely. A general rule of thumb is to shoot for a ratio of 1:300 (1 square foot of ventilation for every 300 square feet of roof surface).
Do Energy-Efficient Roofs Really Save You Money?
Energy-efficient roofs pay for themselves. They can lower your utility bills by as much as 25 percent. For an average home, the savings can add up to $300 to $500 a year.
Some states and municipalities offer rebates for cool roofs. You can even earn a tax credit through the Energy Star rating program.
What Type of Roof Is the Most Energy Efficient
Types of Roofs
Metal roofing is by far one of the best choices you can make for your roof in general. They’re the most energy-efficient roof for residential installations, can last more than 50 years, and require very little maintenance.
Metal roofs are very reflective, which is why they get so hot to the touch. Much of the sun’s energy is coming right back off the roof. That means they have a high SRI.
And they can be covered with special coatings to give them an even higher efficiency rating.
Tile roofs are also a good energy-efficient roof choice. They can be made from slate, clay or concrete. They can be pre-treated to maximize heat reflectivity. And if you’ve already installed them, don’t worry. They can be treated with reflective coatings even after installation.
Tile roofs also allow air to flow under the tiles which adds to their ability to release any heat they do absorb.
Asphalt shingles are the most common type of roofing material used on homes. Traditionally, they’re also one of the most non-reflective and heat-absorbent roofing options available.
Fortunately, that has changed in recent years. Advances in roofing technology means asphalt shingles are more efficient than ever before.
Today, manufacturers are creating new lines of asphalt shingles with solar-reflecting granules that raise the SRI value and even extend the life of the roof by keeping surface temperatures low.
Owens Corning’s “Cool Roofing Collection” is a good example. It includes shingles with a reflectance value over 20. They even come in darker colors that are normally associated with low solar reflectance values.
Bear in mind, many asphalt shingles don’t have these energy-efficient features. Without the solar-reflecting granules, an asphalt shingle roof may be as much as 100 degrees hotter. And that heat’s going to transfer into your attic and then into your home.
Energy Star Rated Roofs
Not all roofs are created equal. Ask your roofer what the Energy Star rating is for the material you’re choosing. A good service roofer will usually deal with several manufacturers and can help you find the right product for your needs.
Are Energy-Efficient Roofs More Expensive?
Energy-efficient roofs may be more expensive initially, but they usually pay for themselves over time.
For example, a metal roof could lower your energy bill by as much as 40 percent in the summer. Cool roofs can also save money with rebates, incentives, and tax credits.
An energy-efficient roof can also save you money by extending the life of your roof. And since your HVAC system doesn’t have to work as hard to cool your home, it will last longer too.
So What are the Benefits of an Energy-Efficient Roof?
An energy-efficient roof can do more than just save you money on your energy bill. Here are just a few of the other ways an energy-efficient roof can pay you back:
- It lowers maintenance costs.
- It adds to your property value or resale value.
- It extends the life of your roof
- It extends the life of your HVAC system.
- It makes your home more comfortable.
- It improves indoor comfort for spaces that aren’t air conditioned, such as garages or covered patios.
- It looks as good or better than a non-energy-efficient roof.
- It lowers peak electricity demand, which can help prevent power outages.
It can even be good for the environment — by reducing the amount of energy needed to cool buildings, energy-efficient roofs reduce power plant emissions.
Is There a Difference Between an Energy-Efficient Roof and a Cool Roof?
The Department of Energy defines a cool roof as “one that has been designed to reflect more sunlight and absorb less heat than a standard roof.” So, basically any energy-efficient roof could qualify as a cool roof.
However, the term “cool roof” is often associated with flat roofs or commercial installations. Cool roofs typically go over an existing roof by adding a reflective coating. That’s not as easy to do over a conventional shingles.
In cities where most of the buildings and homes have flat roofs, cool roofs can make a big difference. They can actually reduce local air temperatures (sometimes referred to as the urban heat island effect).
Energy-Efficient Roofs: The Smart Choice
Energy-efficient roofs (including cool roofs) are becoming the norm in roofing. Some cities even require all new roofing to meet some solar reflectance minimum.
But even if it’s not required, the benefits of an energy-efficient roof are worth considering before you pick your next roof.
Utekelezaji mzuri wa nishati nyumbani umekuwa suala la kawaida kwa miaka mingi. Vifaa vya nyumbani, mifumo ya HVAC, madirisha ya kuokoa nishati, na hata balbu za LED zote zinaahidi kuokoa nishati na kupunguza gharama. Je, unajua kwamba paa la umeme ni moja ya njia bora za kuokoa nishati? Paa lenye kutumia nishati kidogo laweza kukuokoa mamia ya dola kila mwaka. Hebu kuchunguza paa nishati-tengenezo na jinsi paa yako inaweza kukusaidia kupunguza bili yako ya nishati na kuweka wewe vizuri zaidi katika mchakato. - Ni nini kinachofanya paa liwe na ufanisi wa nishati? - Je, kweli paa zenye kutumia nishati kidogo hukupunguza pesa? - Ni aina gani ya paa inayoweza kutumia nishati kwa njia bora zaidi? - Je, ni ghali zaidi? - Faida na hasara zake ni zipi? Je, kuna tofauti kati ya paa la nishati na <unk> paa baridi<unk>? - Je, kuna tofauti kati ya paa zenye kutumia nishati kidogo na paa zenye baridi? Ni Nini Kinachofanya Paa Liwe na Uwezo wa Kutumia Nishati? Kulingana na GreenBuildingAlliance, 90% ya paa nchini Marekani ni mbaya iliyoundwa na kujengwa na giza, vifaa visivyo na kutafakari ambayo kunyonya badala ya kutafakari joto. Joto la juu ya paa la nyumba inaweza kuwa na joto la nyuzi 90 hadi 100 zaidi ya joto la nje. Kwa paa lenye giza, joto huingia kwenye ghorofa yako ya juu na, hatimaye, nyumbani mwako. Ingawa kutenganisha vizuri hutoa misaada fulani, haukuzuia uhamisho wa joto kutoka juu ya paa hadi kwenye ghorofa ya juu. Wakati paa yako ni overheated, joto ziada itakuwa kuhamishwa ndani ya nyumba yako na kufanya A&C kazi ngumu zaidi kuliko inapaswa. Sababu mbili huathiri uwezo wa paa wa kuzuia uhamisho huu wa joto: mwangaza wa jua na uingizaji hewa. Kiwango cha Reflectance ya Jua Kiwango cha Reflectance ya Jua hupima uwezo wa paa kukataa joto la jua (reflectance ya jua) na kutolewa joto lolote ambalo huchukuliwa (emissivity ya joto). Kadiri idadi ya SRI ilivyo kubwa ndivyo inavyokuwa bora. Maabara ya Taifa ya Lawrence Berkeley imegundua kuwa kuongeza kiwango cha SRI kutoka 25 hadi 40 inaweza kupunguza joto la uso wa paa kwa zaidi ya digrii 13. Hii inaweza kuokoa hadi 15% ya bili yako ya nishati. Rangi nyepesi huonyesha joto vizuri kuliko rangi nyeusi, na mipako fulani yaweza kuongeza mwangaza zaidi. Lakini ufunguo wa paa lenye ufanisi wa nishati ni kwamba litaonyesha mnururisho wa jua mbali na nyumba. Hilo lamaanisha kwamba joto kidogo hupelekwa kwenye ghorofa ya juu. Kwa sababu ya hali ya hewa ya juu, joto la chini linahamishwa kwenye nyumba yako. Mtazamo wa jua unaweza kuonekana kuwa mdogo katika hali ya hewa baridi, lakini hata kama unaishi mahali ambapo majira ya joto ni mafupi, uokoaji unaweza kuongezeka. Jambo jingine linaloweza kufanya paa lisiwe baridi ni uingizaji hewa. Upepo mzuri huzuia joto lolote linalopelekwa kwenye ghorofa ya juu lisijitokeze. Joto la nje ni juu ya 90 ° C, na joto la juu la ghorofa ya juu inaweza kufikia digrii 160. Na joto hilo lazima liende mahali fulani. Bila uingizaji hewa wa kutosha, inaweza kuenea ndani ya nyumba. Na ikiwa joto linakuwa kali sana, si tu kwamba itakuongeza bili yako ya umeme - kwa kweli inaweza kuharibu paa lako. Vents static, vents upepo powered na vents eclectic ni aina tatu kuu ya vents paa kutumika katika makazi paa. Kila moja ina faida na hasara zake. Ni njia gani ya hewa ya hewa ya hewa ya hewa ya hewa ya hewa ya hewa ya hewa ya hewa ya hewa ya hewa ya hewa ya hewa ya hewa ya hewa ya hewa ya hewa ya hewa ya hewa ya hewa ya hewa ya hewa ya hewa ya hewa ya hewa ya hewa ya hewa ya hewa ya hewa ya hewa ya hewa ya hewa ya hewa ya hewa ya hewa ya hewa. Kwa kawaida, kiwango cha hewa ni 1: 300 (mita ya mraba ya uingizaji hewa kwa kila mita ya mraba ya paa). Je, Kwa Kweli Paa Zinazotumia Nishati Bora Hukuokoa Pesa? Paa zenye kutumia nishati kwa njia bora hulipa gharama zake zenyewe. Unaweza kupunguza bili za huduma za umma kwa asilimia 25. Kwa nyumba ya kawaida, akiba hiyo inaweza kuongezeka hadi dola 300 hadi 500 kwa mwaka. Majimbo na manispaa fulani hutoa punguzo kwa ajili ya paa baridi. Unaweza hata kupata mkopo wa kodi kupitia programu ya kiwango cha Nishati ya Nishati. Aina ya paa ya chuma ni moja ya chaguzi bora unaweza kufanya kwa paa yako kwa ujumla. Ni paa la nishati ya ufanisi zaidi kwa mitambo ya makazi, inaweza kudumu zaidi ya miaka 50, na inahitaji matengenezo machache sana. Paa za chuma huonyesha sana, ndiyo sababu zina joto sana zinapoguswa. Nishati nyingi za jua zinarudi kutoka kwenye paa. Hii inamaanisha kuwa wana kiwango cha juu cha SRI. Na zinaweza kufunikwa kwa mipako maalum ili kuwapa kiwango cha juu zaidi cha ufanisi. Paa la matofali pia ni chaguo zuri la paa lenye kutumia nishati kwa njia bora. Zinaweza kutengenezwa kwa chokaa, udongo, au saruji. Wanaweza kuwa pre-kutibiwa ili kuongeza joto reflectivity. Na kama tayari umeweka, usijali. Wanaweza kutibiwa na mipako ya kutafakari hata baada ya ufungaji. Paa la tile pia huruhusu hewa kutiririka chini ya vigae ambayo inaongeza uwezo wao wa kutolewa joto lolote wanachukua. Vipande vya lami ni aina ya kawaida ya paa inayotumiwa kwenye nyumba. Kwa kawaida, wao pia ni moja ya chaguzi zaidi zisizo za kutafakari na za kunyonya joto zinazopatikana. Kwa bahati nzuri, hali hiyo imebadilika katika miaka ya karibuni. Maendeleo katika teknolojia ya paa yanamaanisha kwamba shingles za lami ni zenye ufanisi zaidi kuliko wakati mwingine wowote. Leo, wazalishaji wanaunda mistari mpya ya shingles ya lami na granules za kutafakari jua ambazo huongeza thamani ya SRI na hata kupanua maisha ya paa kwa kuweka joto la uso chini. Owens Corning's "Cool Roofing Collection" ni mfano mzuri. Shingles ni aina ya shingles ambayo ina kiwango cha mwangaza wa juu kuliko 20. Hata zinapatikana katika rangi nyeusi ambazo kwa kawaida huhusianishwa na maadili ya chini ya mwangaza wa jua. Kumbuka, shingles nyingi za lami hazina sifa hizi za ufanisi wa nishati. Bila granules ya jua, paa la asphalt linaweza kuwa na joto la digrii 100 zaidi. Na joto hilo litaingia kwenye ghorofa yako ya juu na kisha ndani ya nyumba yako. Paa Zilizochaguliwa na Nyota za Nishati Si paa zote zilizotengenezwa sawa. Uliza roofer yako nini Energy Star rating ni kwa ajili ya nyenzo wewe ni kuchagua. Mfanyakazi mzuri wa paa kwa kawaida atashughulika na wazalishaji kadhaa na anaweza kukusaidia kupata bidhaa sahihi kwa mahitaji yako. Je, Paa Zinazotumia Nishati Bora Ni Za Ghali Zaidi? Paa zenye kutumia nishati kidogo huenda zikawa ghali zaidi mwanzoni, lakini kwa kawaida hulipwa kwa wakati. Kwa mfano, paa la chuma linaweza kupunguza gharama za umeme kwa asilimia 40 wakati wa kiangazi. Paa zenye baridi pia zaweza kuokoa pesa kwa kutoa punguzo, vichocheo, na mikopo ya kodi. Paa lenye matumizi ya nishati ya kutosha linaweza pia kukuokoa pesa kwa kupanua maisha ya paa lako. Na kwa kuwa mfumo wako wa HVAC hauhitaji kufanya kazi kwa bidii ili kupoza nyumba yako, itadumu kwa muda mrefu pia. Kwa hiyo, ni faida gani za paa lenye kutumia nishati kwa njia nzuri? Kwa hiyo, paa la umeme linaweza kufanya mengi zaidi ya kuokoa pesa kwenye bili yako ya umeme. Hapa ni baadhi ya njia ambazo paa la umeme linaweza kukusaidia: - Inaongeza thamani ya mali yako au thamani ya kuuza tena. Inaongeza maisha ya paa yako na mfumo wako wa HVAC. - Inafanya nyumba yako iwe yenye starehe zaidi. - Inaongeza starehe ya ndani kwa ajili ya nafasi ambazo si air conditioned, kama vile karakana au patios kufunikwa. - Inaonekana nzuri au bora kuliko paa lisilo na ufanisi wa nishati. - Inapunguza mahitaji ya umeme ya kilele, ambayo inaweza kusaidia kuzuia kukatika kwa umeme. Inaweza hata kuwa nzuri kwa mazingira <unk> kwa kupunguza kiasi cha nishati inahitajika baridi majengo, paa nishati ufanisi kupunguza uzalishaji wa mitambo ya umeme. Je, Kuna Tofauti Kati ya Paa Linalotumia Nishati kidogo na Paa Linalotumia Baridi? "Kifungu cha nishati cha Marekani kinafafanua paa la baridi kama ""ambao limeundwa kutafakari mwangaza zaidi wa jua na kunyonya joto kidogo kuliko paa la kawaida"" na ""linatumia joto la chini zaidi kuliko paa la kawaida.""" Hata hivyo, neno " paa baridi " mara nyingi huhusianishwa na paa tambarare au mitambo ya kibiashara. Kwa kawaida paa zenye baridi hupita juu ya paa lililopo kwa kuongeza tabaka la kutafakari. Hiyo si rahisi kufanya juu ya shingles ya kawaida. Katika miji ambako majengo na nyumba nyingi zina paa tambarare, paa zenye baridi zaweza kufanya tofauti kubwa. Kwa kweli zinaweza kupunguza joto la hewa la mahali hapo (wakati mwingine huitwa athari ya kisiwa cha joto cha mijini). Sehemu ya juu ya paa: Sehemu ya juu ya paa ya paa ya paa ya paa ya paa ya paa ya paa ya paa ya paa ya paa ya paa ya paa ya paa ya paa ya paa ya paa ya paa ya paa ya paa ya paa ya paa ya paa ya paa ya paa ya paa ya paa ya paa. Majiji fulani hata huhitaji paa zote mpya zipatane na kiwango cha chini cha kutafakari jua. Lakini hata kama si required, faida ya paa nishati-efficient ni thamani ya kuzingatia kabla ya kuchagua paa yako ijayo.