How to Compare Greenhouse and Growing-System Proposals
How to compare commercial greenhouse, climate-control and fertigation proposals fairly: a clear technical brief, scope normalisation, CAPEX and OPEX assumptions, water and energy inputs, service, spare parts, expandability and risk — plus an RFQ checklist.
How do you compare greenhouse quotes fairly?
Issue one brief, require a line-by-line response, mark every scope item included, excluded or unclear, price the gaps, then compare technical fit, TCO, delivery, service and risk. Only after scope and design conditions are normalised. On its own it hides exclusions and different climate assumptions.
Key takeaways
- Why are greenhouse quotes so hard to compare?: Because suppliers price different scopes.
- What should the technical brief contain before you request proposals?: The brief is the yardstick.
- How do I normalise scope across proposals?: Build a scope matrix with one row per item and one column per proposal.
- Illustrative worked example: comparing on the same scope: Hypothetical figures for method only — not market prices.
- How should CAPEX and OPEX assumptions be compared?: Ask each supplier to state the inputs behind any energy, water or labour figure they quote, then recalculate them with your local tariffs and quantities.
Short answer: you can only compare greenhouse proposals that answer the same brief. Issue one technical and commercial specification, ask every supplier to respond line by line, normalise what is included and excluded, then compare technical fit, total cost over the operating life, delivery, service and risk — not just the headline price per square metre.
In this guide a proposal is a supplier's technical and commercial offer for a greenhouse, a growing system (for example substrate gutters or hydroponic channels), greenhouse climate control equipment or a fertigation system. Total cost of ownership (TCO) means purchase and installation cost plus the operating, maintenance and replacement costs over the period you plan to run the facility.
Why are greenhouse quotes so hard to compare?
Because suppliers price different scopes. One offer may include foundations, the fertigation head and commissioning; another may exclude them or assume the buyer provides water treatment, electrical work or cranes. Design assumptions also differ: a cooling system sized for a milder hot day than your site actually sees will look cheaper and perform worse. Price per m² hides all of this.
What should the technical brief contain before you request proposals?
The brief is the yardstick. It should state the crop and growing method, net and gross area, location and design climate (hot-day, cold-night, wind and, where relevant, snow), water analysis and available flow, electricity capacity and tariff basis, required systems by function, automation level, commissioning tests, training, warranty and spare-parts expectations, delivery schedule and phasing. Our guide on how to plan and procure a commercial greenhouse walks through each item.
How do I normalise scope across proposals?
Build a scope matrix with one row per item and one column per proposal. Mark each cell included, excluded or unclear, and send every unclear item back as a clarification question before scoring.
| Scope item | Proposal A | Proposal B | Proposal C |
|---|---|---|---|
| Structure and covering to stated loads | Included | Included | Included |
| Ventilation, screens and cooling to stated hot-day condition | Included | Included | Unclear — design condition not stated |
| Heating to stated cold-night condition | Included | Excluded | Included |
| Water treatment and fertigation head | Included | Excluded | Included |
| Climate computer, sensors and alarms | Included | Included | Included |
| Foundations and civil works | Excluded | Excluded | Excluded |
| Installation, commissioning and training | Included | Included | Supervision only |
| Recommended spare parts | Listed | Not listed | Listed |
Illustrative worked example: comparing on the same scope
Hypothetical figures for method only — not market prices. Proposal A is quoted at USD 1,000,000; Proposal B at USD 850,000 but excludes heating and the fertigation head; Proposal C at USD 920,000 with supervision-only installation. To compare like for like, the buyer prices the missing items using separate quotations or their engineer's estimate — say USD 120,000 for B's missing systems and USD 60,000 for C's installation labour. Normalised: A = 1,000,000; B = 970,000; C = 980,000. The gap shrinks from 15% to 3%, and the decision now rests on technical fit, operating cost, service and risk.
Use the greenhouse bid comparison tool to lay out your own proposals in the same way.
How should CAPEX and OPEX assumptions be compared?
Ask each supplier to state the inputs behind any energy, water or labour figure they quote, then recalculate them with your local tariffs and quantities. The greenhouse TCO calculator and the operating cost calculator let you enter the same assumptions for every proposal. Keep three rules:
- Use one set of buyer-confirmed tariffs, water costs and wage rates for all proposals.
- Do not accept savings percentages without the measured basis behind them.
- Show low, base and high cases, because energy and input prices move.
Calculator outputs are indicative and depend on what you enter. Use them to test the sensitivity of a decision, not as a substitute for supplier data or engineering review.
What water and energy inputs should proposals declare?
For climate systems: design conditions, installed electrical load, fan and pump power, heating capacity and fuel type, and expected water use for evaporative cooling. For irrigation and fertigation: design flow, filtration level, number of dosing channels, EC/pH control method, drain handling and any disinfection. Check every figure against your own loads from the cooling calculator, heating load calculator and fertigation calculator.
How do I judge compatibility between systems?
Climate, irrigation and fertigation work as one production environment. Ask how the climate computer integrates with irrigation and dosing, which communication protocols and sensors are used, who is responsible for integration if packages come from different suppliers, and whether data can be exported. An incompatible control layer is one of the costliest problems to fix after handover.
Service, spare parts and expandability
| Area | What to ask |
|---|---|
| Service | Local or remote support, response times, training, who commissions |
| Spare parts | Recommended list, local stock, lead times for critical items (pumps, dosing, controllers) |
| Warranty | What is covered, for how long, and what voids it |
| Software | Licences, subscriptions, update policy and data ownership |
| Expandability | Whether phase two can connect to structure, water, power and controls without rework |
How do I score the proposals?
Agree weights before you open prices so the price does not drive the scoring. A simple weighted scorecard might weight technical compliance, total cost over the planned operating period, delivery and installation plan, service and spare parts, and risk (contract terms, financial standing, references you can verify). Use weights that reflect your project; there is no standard set.
Greenhouse supplier RFQ checklist
- Crop, growing method, area and phasing.
- Location, design climate and loads.
- Water analysis, available flow and discharge rules.
- Electricity capacity, tariff basis and backup requirement.
- Functional requirement for structure, covering, ventilation/cooling, heating, screens, irrigation, fertigation, sensors and controls.
- Line-by-line compliance response required.
- Explicit included/excluded scope list, including civil, electrical and installation.
- Declared energy, water and labour assumptions.
- Commissioning acceptance tests, training and documentation.
- Warranty, service, spare parts and software terms.
- Delivery schedule, payment milestones and validity of the offer.
Financing and payment terms
Payment milestones, guarantees and any financing options shape the real cost and risk of a proposal, so record them in the comparison. Information on financing is general guidance only: approval and terms depend on lenders or other providers and on your project, and are never guaranteed. See project financing for background.
Like-for-like RFQ checklist by package
Ask every bidder to answer the same lines. Mark each as included, excluded or unclear; an unclear line is a question to resolve before comparing totals.
| Package | Buyer provides | Bidder must state |
|---|---|---|
| Site and climate | Location, survey, soil report, design temperatures, wind and snow data | Design loads and climate basis assumed |
| Crop plan and capacity | Crops, planting schedule, usable area, target output range | Net growing area, bay layout, planting density used |
| Structure | Preferred type, gutter height, expansion direction | Structural standard, steel grade and coating, foundation scope |
| Covering | Light and insulation priorities | Material, expected service life, replacement assumptions |
| Ventilation | Climate data | Vent area as % of floor area, insect screen effect on airflow |
| Heating and cooling | Design conditions, available fuels, water for cooling | Capacity basis, equipment, energy source and consumption assumptions |
| Irrigation and fertigation | Crop, substrate, water analysis | Dosing units, zones, drain handling, recirculation |
| Water treatment | Water analysis and discharge rules | Filtration, RO or disinfection scope and capacity |
| Controls | Required functions, data access | Climate computer, sensors, integration responsibility, data export |
| Energy | Grid capacity, tariffs, backup needs | Connected load, backup power, metering |
| Installation | Site access, local labour rules | Who installs, supervision, programme, site facilities |
| Commissioning | Acceptance expectations | Test procedures, acceptance criteria, training, documentation |
| Maintenance and spares | Service expectations | Recommended spares list, service response, warranty terms |
| Expansion | Future phases | How later phases connect to structure, utilities and controls |
Validation note: this checklist organises proposals; it does not replace local structural engineering, permitting checks or agronomic review. Those may be required before contract award.
Record each normalised proposal in the bid comparison tool and check lifecycle cost with the TCO calculator.
How SeedMatch helps
SeedMatch Group is supplier-neutral and human-reviewed. Buyers use our guides, calculators and RFQ tools free of charge and are under no obligation to work with us. When you submit a project, our team reviews and structures the request, manages supplier outreach and helps you compare the proposals on the same basis. We do not expose supplier contact details or promise prices, availability, savings or outcomes.
Prepare your brief in the free greenhouse RFQ or the RFQ builder and see how SeedMatch sourcing works.
Turn "How to Compare Greenhouse and Growing-System Proposals" into your RFQ
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Frequently asked questions
- How do you compare greenhouse quotes fairly?
- Issue one brief, require a line-by-line response, mark every scope item included, excluded or unclear, price the gaps, then compare technical fit, TCO, delivery, service and risk.
- Is price per square metre a good comparison metric?
- Only after scope and design conditions are normalised. On its own it hides exclusions and different climate assumptions.
- What should a greenhouse RFQ include?
- Crop, area, location and design climate, water and power data, functional system requirements, a scope list, declared operating assumptions, commissioning tests, service and spare-parts terms, schedule and payment milestones.
- How do I compare energy and water costs between proposals?
- Ask for the inputs behind each figure and recalculate all proposals with your own local tariffs and quantities, using low, base and high cases.
- Can I rely on calculator results for the decision?
- Use them to test assumptions and sensitivity. They are indicative planning figures, not supplier data, engineering designs or quotes.
- Does SeedMatch contact suppliers for me?
- Yes. After reviewing your submitted project, our team manages supplier outreach and helps you compare responses. The service is free for buyers, with no obligation.
Move from reading to sourcing
The pages below carry the commercial detail for this topic — cost ranges, supplier verification, specification checklists and financing routes.