Cost Calculator: Prefab vs Brick & Mortar
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May 27, 2025
Cost Calculator: Prefab vs Brick & Mortar
Why bother with a cost calculator?
Hidden costs decide ROI, not sticker price. A brick wall that looks “cheap” at ₹90 /sq ft can push refrigeration bills up by 30-40 % for 20 years.
Speed-to-revenue matters. Every week your facility opens early is a week of produce saved, SKUs shipped, or vials validated. Prefab builds 30-50 % faster.
Lifecycle ≥ construction. PIR/PUF panels last 25-30 years with wipe-clean maintenance; masonry needs repainting, waterproofing and crack repair every 5-7 years.
Step-by-step cost calculator framework
| Input | Prefab best-practice (Default) | Brick & mortar (Default) |
|---|---|---|
| 1. Envelope cost/ sq ft | ₹450 (100 mm PIR, colour-coat steel) | ₹1,950 (9″ brick + RCC columns, plaster, paint) |
| 2. Build time | 4 months (10,000 sq ft cold store) | 8 months |
| 3. Refrigeration load (TR/ 100 m²) | 55 | 78 (+41%) |
| 4. Annual kWh | 480,000 | 690,000 |
| 5. Energy cost (₹/kWh) | User input (default ₹8) | |
| 6. O&M (% of capex/ yr) | 0.5% | 2.5% |
Formulae
- Capex = Envelope × floor area + HVAC + floor & services
- Lost revenue = Daily GM × (delivery delay days)
- Energy (₹/yr) = Annual kWh × unit cost
- Lifecycle cost (20 yr NPV @10 %) = Capex + Σ(energy + O&M – tax shield)
Replace the grey cells and the sheet spits out Payback-in-months and 20-yr NPV delta for prefab vs brick.
Key cost drivers unpacked
1. Building shell
Prefab: 100 mm PIR panel wall/roof gives U-values around 0.28 W/m²K and cuts heat ingress by ~82 % vs 150 mm brick without insulation
Brick: Needs 75-100 mm external insulation or cavity wall to reach ECBC U-factor of 0.261 W/m²K; rarely installed in industrial budgets.
2. Time = money
Factory-made panels and bolted steel frames slash on-site labour; studies show 40 % faster schedules (and even 2× in Tata Steel Nest-In projects)
For a 10 000 sq ft ripening hub earning ₹2 lakh/day GM, four months saved equals ₹2.4 cr opportunity cost avoided.
3. Energy & refrigeration
PUF/PIR cores (λ ≈ 0.022 W/mK) trim HVAC energy 30-40 % and, in a World-Bank/BEE study, paid back in 3-5 years for apple, grape and mango pack-houses .
A 5 000 MT cold store case cut wall heat load from 35 MWh to 21 MWh (-41 %) with 100 mm PIR
4. Maintenance & lifespan
Colour-coated steel skins resist corrosion; routine care is quarterly wash-downs and gasket checks. Expected life 25-30 yrs
Masonry requires crack grouting, repainting, damp-proofing—estimated at 2.5 % capex/year
Industry-specific snapshots
Cold-storage & 3PL warehousing
A 20 000 sq ft PIR-panel warehouse recoups extra envelope cost in 2.1 yrs via energy savings and rental income acceleration.
Food & beverage processing
HACCP grade finishes (steel skins, concealed fasteners) avoid plaster flakes—saving ₹4 lakh/year on product recalls and downtime.
Pharma & life-science clean-rooms
PIR panels meet WHO GDP fire-policy; leak-free joints cut re-validation cycles, trimming ₹15 lakh annual compliance overheads.
Data-centre white-space
FM-approved PIR with 2-hr fire rating slots into modular pods; every 10 % envelope energy cut yields 1 % PUE improvement.
How to use the calculator
- Grab base rates. Enter your local steel/PIR quote (₹/sq ft) and current grid tariff.
- Choose build size & usage. The model autoscales HVAC tonnage and operating hours.
- Stress-test. Toggle interest rate, depreciation regime, or a 5 % energy-price CAGR.
- Compare scenarios. Print the summary tab for board approvals or lender due-diligence.
Final takeaways
- Capex parity is a myth. Wall-roof packages are cheaper today, and full-facility prefabs close the gap once time and financing are priced in.
- Operating cost edge is structural. Better U-values mean lower compressors, smaller gensets and thinner energy bills for decades.
- Regulatory & ESG upside. ECBC, FSSAI, WHO-GDP and LEED credits all tilt towards high-performance envelopes.
Ready to model your own numbers?
Rinac’s in-house engineering team can preload your area, temperature band and subsidy scheme into the calculator and mail you a one-pager ROI sheet. Leave your email in the comments or ping [email protected], and we’ll spin it up in 24 hours.
June 9, 2025
