Give everyone assessing your home the same information
Comparison starts before the proposals arrive. Prepare a shared description of the floor area and layout, normal use, desired services, existing installation and planned renovations. Add plans and photographs where available. If each professional receives a different scenario, their solutions may also differ for valid reasons.
Separate confirmed requirements from alternatives. For example, preferring to keep radiators is different from requiring cooling in every room. Ask for any matters awaiting a visit or further checks to be identified. A preliminary proposal should be distinguishable from one based on a completed assessment.
Check which services and spaces are covered
Look for a clear list of heating, cooling and hot water services, with the relevant zones or points of use. A reversible heat pump does not mean every existing emitter can provide cooling. Similarly, mentioning domestic hot water does not explain the storage solution on its own.
Make a simple table by room and service. Note if one quotation excludes a bedroom or uses a different system in summer. These differences need resolving before prices are compared. Otherwise, you will be treating installations intended to achieve different outcomes as equivalent.
Identify the equipment and how it was selected
Ask for specific references for the main components, including controls and indoor equipment. A broad commercial product name may cover several configurations. Also request a clear explanation of how capacity was selected and which features of the home were considered.
Do not choose simply by the highest kilowatt rating or an isolated efficiency figure. Catalogue data relates to particular test conditions. For a useful comparison, you need to know whether the options were assessed against the same comfort objectives and assumptions about insulation, emitters and hot water.
Review the work connecting the system to your home
An installation includes service routes, supports, connections and adaptation to the available spaces. Ask what each proposal covers for the electrical supply, pipework, drainage, access panels and finishes. If another trade is responsible for some work, you need to know so it can be coordinated and the total scope assessed.
Also clarify which existing components will remain and which require checking first. A quotation need not reproduce a complete technical design to be understandable, but it should identify inclusions, exclusions and assumptions. Broad wording deserves an explanation before a decision is made.
Compare commissioning and handover
Ask which checks will be carried out at completion, which documents you will receive and how operation will be explained. Include the specific maintenance and aftercare terms proposed, without assuming cover that is not set out in writing.
Once the options are complete, summarise the differences affecting your decision: building work, space occupied, services, controls and responsibilities. Ask for any important uncertainty to be clarified before accepting. A good choice is not about collecting more catalogue pages, but understanding the solution your home will have and the work needed to make it operate.
More common questions
Do two units with the same output provide the same installation?
No. Their configuration, operating conditions and included components can differ. Emitters, distribution and controls also matter.
What should I do if a proposal leaves some items undefined?
Ask for their scope, who will carry them out and which checks they depend on to be clarified. You can then compare the complete proposals on the same basis.
Sources and technical reading
Some source documents are available in Spanish.