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Decision matrix (weighted / Pugh) templates

Decision Matrix — School Heating Options Appraisal

An options appraisal for replacing a secondary school's heating, with like-for-like gas as the baseline and the trust's 120 tCO₂e carbon cap as a must-have that excludes both gas and the hybrid. A district heat connection ranks first at 3.69 of 5 — 0.49 above the gas baseline and 0.33 ahead of air-source heat pumps. Illustrative values.

Decision matrix (weighted / Pugh)Project & PlanningDecision matrix (weighted / Pugh) syntax docs
Template previewDecision matrix (weighted / Pugh)
Secondary school heating replacement — options appraisalSecondary school heating replacement — options appraisalLike-for-like gas is the baseline; the trust's net-zero plan caps carbon at 120 tCO₂e a yearWeighted scoringScale 1–56 criteria5 optionsBaseline: Like-for-like gas boilersCRITERIONWEIGHTLike-for-likegas boilersEXCLUDEDAir-source heatpumpsGround-sourceheat pumpsHybrid ASHP +gasEXCLUDEDDistrict heatconnectionRECOMMENDEDCapital cost after grantmeasured, £k · lower is better25%£420kscore 5£1,180kscore 2.5−£1,640kscore 1−£860kscore 3.6−£940kscore 3.3−Annual running costmeasured, £k · lower is better20%£96kscore 1£78kscore 3.3+£64kscore 5+£88kscore 2+£82kscore 2.8+Annual carbonmeasured, tCO₂e · lower is better · must ≤ 120tCO₂e25%298 tCO₂escore 174 tCO₂escore 4.7+58 tCO₂escore 5+142 tCO₂escore 3.6+66 tCO₂escore 4.9+Disruption to teaching (1 = minimal)lower is better10%13−5−2−3−Resilience in a cold snap10%53−4−54−Fabric readiness (low-temperature heat)10%53−3−4−4−Weighted scoreΣ weight × score, of 53.2064% of max3.3667.2% of max3.3066% of max3.4969.8% of max3.6973.8% of maxvs baselinechange in weighted scorebaseline+0.162 better · 4 worse+0.102 better · 4 worse+0.292 better · 3 worse+0.492 better · 4 worseRankhighest score firstexcluded2nd3rdexcluded1stWeighted totalsEach bar is split into its criteria's weighted contributions (colours match the dots in the table); ranked best first.012345District heat connection3.6973.8%Air-source heat pumps3.3667.2%Ground-source heat pumps3.3066%Like-for-like gas boilers3.2064%excluded — fails a must-haveHybrid ASHP + gas3.4969.8%excluded — fails a must-havebaselineFINDINGS & SENSITIVITYMODERATEDistrict heat connection ranks first at 3.69 of 5 (73.8%), 0.33 ahead of Air-source heat pumps.Sensitivity (moderate): Ground-source heat pumps draws level with District heat connection if the weight on “Annual running cost” rises from 20% to 31.8% (+11.8points), the other weights rescaled in proportion — the smallest single-weight change that changes the winner.Ground-source heat pumps would draw level by scoring 1.1 instead of 5 on “Disruption to teaching (1 = minimal)” — the smallest single-score change that would.Against the baseline “Like-for-like gas boilers”: District heat connection adds 0.49 points, better on 2 criteria and worse on 4 criteria.Like-for-like gas boilers is excluded — it fails a must-have (“Annual carbon” is 298 tCO₂e, must be ≤ 120 tCO₂e), so its total of 3.20 is not ranked.Hybrid ASHP + gas is excluded — it fails a must-have (“Annual carbon” is 142 tCO₂e, must be ≤ 120 tCO₂e), so its total of 3.49 is not ranked.Illustrative costs and carbon for a fictional 1,100-pupil school; capital is net of the decarbonisation grant.

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title "Secondary school heating replacement — options appraisal"
subtitle "Like-for-like gas is the baseline; the trust's net-zero plan caps carbon at 120 tCO₂e a year"
baseline "Like-for-like gas boilers"
note "Illustrative costs and carbon for a fictional 1,100-pupil school; capital is net of the decarbonisation grant."

options "Like-for-like gas boilers" | "Air-source heat pumps" | "Ground-source heat pumps" | "Hybrid ASHP + gas" | "District heat connection"

"Capital cost after grant"  weight 25 unit "£k" lower        : 420 1,180 1,640 860 940
"Annual running cost"       weight 20 unit "£k" lower        : 96 78 64 88 82
"Annual carbon" weight 25 unit "tCO₂e" lower must <= 120     : 298 74 58 142 66
"Disruption to teaching (1 = minimal)" weight 10 lower       : 1 3 5 2 3
"Resilience in a cold snap" weight 10                        : 5 3 4 5 4
"Fabric readiness (low-temperature heat)" weight 10          : 5 3 3 4 4