Natural gas vs propane: the fine print that decides your bill

Natural gas vs propane: the fine print that decides the bill

The salesperson knocks on the door with a 20% discount on consumption and the promise of adapting the boiler for free. The critical point, as several participants warn, is not the price per kilowatt hour, but a charge that rarely appears in the offer: the building fee (canon de finca). A charge that, according to these accounts, is collected for years to finance the installation of natural gas in the building and that can turn an apparent saving into a bill more expensive than that of piped propane.

The price comparison is misleading if you don't look at the fixed term. Piped propane is billed by kilograms, with a maximum price before taxes of 68.6449 cts/kg and a lower heating value of 11,082 kcal/kg, which puts the kWh at about 5.6 cts (VAT excluded), according to a calculation circulating in the thread. Natural gas on the TUR 3.2 tariff has a variable term of €0.040137088/kWh and a fixed term of €8.67/month. At first glance, natural gas wins. But you have to add the building fee, which in some communities, according to participants, far exceeds those €8.67 per month.

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The building fee: the hidden cost that finances the pipeline

Installing natural gas in a building is expensive. Gas Natural finances the work, but recovers it through a monthly charge that appears on the bill under the name of building fee, according to several users. This charge is not a tax or a municipal fee: it is the debt the building incurs with the supplier, according to these accounts. In communities where the installation is already in place, the fee can be several euros a month; in others, it has been paid in advance by the residents.

The salesperson's offer usually doesn't mention this detail. It talks about a 20% discount on consumption, but not about fixed costs. The fixed term of natural gas (€8.67/month on TUR 3.2) is higher than that of piped propane (€1.56/month), but the building fee can push it up even further. That's where the risk lies: the saving on consumption can be eaten up by the fixed charge.

Is the switch worth it? It depends on consumption and the fine print

There is no single answer. For high consumption, natural gas works out cheaper because the price per kWh is lower. For low consumption, piped propane can be more economical because the fixed term is lower and there is no building fee. A calculation circulating in the sector puts the break-even point at around 5,000 kWh per year. Below that figure, propane pays off; above it, natural gas.

But there are more factors. Boiler adaptation is free, but it involves changing the injectors. Propane has a higher heating value, so the injectors are smaller; when switching to natural gas, they are replaced with larger-diameter ones. The work is done by the technical service and does not affect the warranty, according to the offer. However, some accounts warn that the installation may require additional adjustments that are not always covered.

The experience of those who have already switched

Real cases show great variability. Some have seen their bill halved with natural gas, while others have paid €700 heating bills with propane. The price difference per kWh between the two fuels is notable: piped propane comes in at around 5.6 cts/kWh, while natural gas on TUR 3.2 drops to 4 cts/kWh. But the building fee and the fixed term tip the balance at low consumption levels.

The decision, therefore, requires looking at the whole bill, not just the consumption price. The salesperson who knocks on the door usually doesn't carry the breakdown of the building fee. Asking for it in writing is the first step to avoid signing blind.