Building energy assessment
and design

Energy refurbishment designs

Two de­sign as­sign­ments show how en­er­gy mod­els and as­sess­ments in­form pro­posed im­prove­ments to pub­lic build­ings.

Energy and electrical systems for a school

En­er­gy, elec­tri­cal-sys­tems and fire-safe­ty de­sign with­in a mul­ti­dis­ci­pli­nary team. Struc­tur­al de­sign was car­ried out by an­oth­er pro­fes­sion­al.

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Reducing an institutional building’s energy demand

En­er­gy as­sess­ment and de­sign cov­er­ing the en­ve­lope, sys­tems and re­new­ables. Post-in­ter­ven­tion per­for­mance fig­ures are de­sign es­ti­mates.

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When is an EPC mandatory for a property?

An EPC (APE) is re­quired, in the cases gov­erned by Art. 6 of Leg­isla­tive De­cree 192/2005, for new build­ings, major ren­o­va­tions and the sale, free trans­fer or new let­ting of build­ings or units. It must be made avail­able dur­ing ne­go­ti­a­tions and at­tached to the con­tract where the law re­quires it; let­ting a sin­gle unit is sub­ject to a dif­fer­ent at­tach­ment rule. Ex­emp­tions and spe­cif­ic pro­vi­sions also exist for cer­tain pro­tect­ed prop­er­ties, so the oblig­a­tion must be checked for the ac­tu­al build­ing and trans­ac­tion. Penal­ties de­pend on the type of breach and con­tract.

What is the 'Green Homes' Directive and when does it apply?

Di­rec­tive (EU) 2024/1275, also known as the 'Green Home­s' Di­rec­tive, sets na­tion­al av­er­age tar­gets for re­duc­ing pri­ma­ry en­er­gy use in the ex­ist­ing res­i­den­tial stock: at least 16% by 2030 and 20–22% by 2035. It does not im­pose a spe­cif­ic en­er­gy-class dead­line on every dwelling, as an ear­li­er pro­pos­al would have done. For new build­ings, the zero-emis­sion stan­dard ap­plies from 1 Jan­u­ary 2028 to those owned by pub­lic bod­ies and from 1 Jan­u­ary 2030 to all oth­ers. The gen­er­al trans­po­si­tion dead­line was 29 May 2026: the ap­plic­a­ble Ital­ian im­ple­ment­ing rules must be checked be­fore at­tribut­ing a spe­cif­ic oblig­a­tion to an in­di­vid­ual prop­er­ty.

How long does an Energy Performance Certificate last?

An EPC has a max­i­mum va­lid­i­ty of ten years, sub­ject to com­pli­ance with statu­to­ry en­er­gy-ef­fi­cien­cy in­spec­tions of the build­ing's sys­tems. It must be up­dat­ed after ren­o­va­tion or en­er­gy works that change the build­ing's en­er­gy class. If the re­quired in­spec­tions are missed, it may ex­pire ear­li­er. The cer­tifi­cate is reg­is­tered in the com­pe­tent re­gion­al system: in Lazio, through APE-Lazio, with data feed­ing into the na­tion­al SIAPE sys­tem.

How do you improve the energy class of a listed historic building?

Im­prov­ing the en­er­gy per­for­mance of a list­ed build­ing re­quires a bal­ance be­tween en­er­gy per­for­mance and pro­tec­tion of the asset: the most in­va­sive en­ve­lope in­ter­ven­tions, such as ex­ter­nal cladding or the full re­place­ment of his­toric win­dow frames, are often in­com­pat­i­ble with the So­print­en­den­za­'s con­straint. Com­pat­i­ble so­lu­tions in­clude in­ter­nal in­su­la­tion with low-im­pact ma­te­ri­als, re­place­ment of heat­ing sys­tems with high-ef­fi­cien­cy ones (for ex­am­ple ra­di­ant pan­els) and the op­ti­mi­sa­tion of ex­ist­ing win­dow frames with com­pat­i­ble dou­ble glaz­ing. A pre­lim­i­nary en­er­gy audit (UNI CEI EN 16247-2), con­duct­ed to­geth­er with the as­sess­ment of con­ser­va­tion con­straints, iden­ti­fies po­ten­tial im­prove­ments to be as­sessed against con­ser­va­tion con­straints and the nec­es­sary au­tho­ri­sa­tions.

What is the difference between an EPC and an energy audit?

The EPC (En­er­gy Per­for­mance Cer­tifi­cate) is a clas­si­fi­ca­tion document: it records the build­ing's en­er­gy per­for­mance on a scale from A4 to G, with a stan­dard­ised method­ol­o­gy (D.M. 26/06/2015). Pro­duc­tion, de­liv­ery and at­tach­ment re­quire­ments de­pend on the cases gov­erned by Art. 6 of Leg­isla­tive De­cree 192/2005. The en­er­gy audit ex­am­ines the build­ing's en­er­gy flows in de­tail, lo­cates the points of loss, sim­u­lates dif­fer­ent in­ter­ven­tion sce­nar­ios with an es­ti­mate of costs and sav­ings, and pro­duces a plan of pri­or­i­ty in­ter­ven­tions. The audit fol­lows the method­ol­o­gy of the UNI CEI EN 16247 stan­dard (Part 2 is spe­cif­ic to build­ings) and helps de­fine en­er­gy re­fur­bish­ment in­ter­ven­tions.

Is a photovoltaic system worthwhile for a hospitality business or as an investment?

Yes. The as­sess­ment de­pends on how the sys­tem will be used. For a hos­pi­tal­i­ty busi­ness, the pho­to­volta­ic sys­tem di­rect­ly re­duces op­er­at­ing costs in a sec­tor with high con­tin­u­ous elec­tric­i­ty con­sump­tion (air con­di­tion­ing, laun­dry, kitchens). The sys­tem must be sized for the busi­ness's ac­tu­al con­sump­tion, not on a stan­dard res­i­den­tial model. For a fam­i­ly of­fice or an in­vestor, a medi­um-scale gen­er­a­tion plant (typ­i­cal­ly under one Megawatt) is a sep­a­rate in­vest­ment. Along­side its tech­ni­cal re­quire­ments, ex­pect­ed re­turns, per­mit­ting timescales, grid con­nec­tion and use­ful life need as­sess­ment, as they would for a prop­er­ty in­vest­ment. The Stu­dio has de­signed pho­to­volta­ic sys­tems of dif­fer­ent sizes and pur­pos­es, from com­mer­cial roofs and in­dus­tri­al sheds to medi­um-scale gen­er­a­tion plants, and can carry out a pre­lim­i­nary tech­ni­cal and fi­nan­cial as­sess­ment in both cases.

Does energy efficiency affect the market value of a property?

It can, but the ef­fect de­pends on the prop­er­ty and its mar­ket. A Bank of Italy study (Ques­tioni di Econo­mia e Fi­nan­za no. 818, 2023), based on res­i­den­tial prop­er­ty list­ings, found that ask­ing prices for homes in the four best en­er­gy class­es were on av­er­age around 25% high­er than those in the worst cat­e­go­ry, after ac­count­ing for the char­ac­ter­is­tics con­sid­ered. The gap varies wide­ly by province. This is nei­ther an es­ti­mate of com­plet­ed sale prices nor a per­cent­age that can be ap­plied to schools, ho­tels or other build­ings. For a spe­cif­ic prop­er­ty, ex­pect­ed costs, con­sump­tion and ben­e­fits must be as­sessed with­out as­sum­ing an au­to­mat­ic in­crease in value.